HELP PLZZZ

Question

When I click on 2 photos a message appears saying "a calling thread cannot access this object because a different thread owns it" I have no clue how to fix this PLZZZ HELP I just started this class so I don't know many key words here is my code
' Match Game
InitializeProgram()
Sub InitializeProgram
'graphics window
GraphicsWindow.Width = 825
GraphicsWindow.Height = 530
GraphicsWindow.BackgroundColor = "LightSkyBlue"
'initialize box locations with covers
Cover = "C:\New folder\gold.png"
BoxW = 150
BoxH = 100
x = 5
y = 5
For I = 1 To 20
BoxX[I] = x
BoxY[I] = y
GraphicsWindow.DrawResizedImage(Cover, BoxX[I], BoxY[I], BoxW, BoxH)
x = x + BoxW + 5
If (x > 4 * BoxW) Then
x = 5
y = y + BoxH + 5
EndIf
EndFor
EndSub
'load images
Photo[1] = "C:\Users\John\Desktop\New folder (2)\gg.jpg"
Photo[2] = "C:\Users\John\Desktop\New folder (2)\ggg.jpg"
Photo[3] = "C:\Users\John\Desktop\New folder (2)\gggg.jpg"
Photo[4] = "C:\Users\John\Desktop\New folder (2)\ggggg.jpg"
Photo[5] = "C:\Users\John\Desktop\New folder (2)\gggggg.jpg"
Photo[6] = "C:\Users\John\Desktop\New folder (2)\ggggggg.jpg"
Photo[7] = "C:\Users\John\Desktop\New folder (2)\gggggggg.jpg"
Photo[8] = "C:\Users\John\Desktop\New folder (2)\ggggggggg.jpg"
Photo[9] = "C:\Users\John\Desktop\New folder (2)\gggggggggg.jpg"
Photo[10] ="C:\Users\John\Desktop\New folder (2)\ggggggggggg.jpg"
Timer.Interval = 1000
Timer.Pause()
Timer.Tick = TickSub
GraphicsWindow.MouseDown = MouseDownSub
Sub MouseDownSub
If (GameStatus = "Playing" And CanClick) Then
'find which box was clicked
x = GraphicsWindow.MouseX
y = GraphicsWindow.MouseY
BoxNumber = 0
For I = 1 To 20
If (x > BoxX[I] And x < BoxX[I] + BoxW) Then
If (y > BoxY[I] And y < BoxY[I] + BoxH) Then
BoxNumber = I
Goto GotIt
EndIf
EndIf
EndFor
GotIt:
If (BoxNumber <> 0) Then
'if already clicked then exit
If (PhotoFound[BoxNumber]) Then
Goto LeaveMouseDownSub
EndIf
ShowPhotoAndCheck()
EndIf
EndIf
LeaveMouseDownSub:
EndSub
'headings
GraphicsWindow.BrushColor = "Black"
GraphicsWindow.FontBold = "false"
GraphicsWindow.FontSize = 20
Heading[1] = Shapes.AddText("Player 1")
Heading[2] = Shapes.AddText("Player 2")
Shapes.Move(Heading[1], 670, 5)
Shapes.Move(Heading[2], 670, 70)
'scores
GraphicsWindow.BrushColor = "White"
GraphicsWindow.FillRectangle(670, 35, 100, 25)
GraphicsWindow.FillRectangle(670, 100, 100, 25)
GraphicsWindow.BrushColor = "Black"
Score[1] = 0
Score[2] = 0
ScoreDisplay[1] = Shapes.AddText(Score[1])
ScoreDisplay[2] = Shapes.AddText(Score[2])
Shapes.Move(ScoreDisplay[1], 715, 35)
Shapes.Move(ScoreDisplay[2], 715, 100)
'Draw message area
GraphicsWindow.BrushColor = "Yellow"
GraphicsWindow.FillRectangle(630, 250, 185, 45)
GraphicsWindow.PenColor = "Black"
GraphicsWindow.PenWidth = 2
GraphicsWindow.DrawRectangle(630, 250, 185, 45)
GraphicsWindow.BrushColor = "Blue"
GraphicsWindow.FontBold = "false"
GraphicsWindow.FontSize = 18
Message = "Game Stopped"
MessageX = 30
MessageArea = Shapes.AddText(Message)
DisplayMessage()
Sub DisplayMessage
Shapes.Move(MessageArea, 630 + MessageX, 260)
Shapes.SetText(MessageArea, Message)
EndSub
'define buttons
GraphicsWindow.BrushColor = "Black"
GraphicsWindow.FontSize = 16
StartStopButton = Controls.AddButton("Start Game", 630, 410)
OptionsButton = Controls.AddButton("Change Options", 630, 450)
ExitButton = Controls.AddButton("Exit", 630, 490)
'Default Options
NumberPlayers = 2
PlayAlone = "true"
Difficulty = 1
SetTitle()
GameStatus = "Stopped"
Sub SetTitle
If (NumberPlayers = 1) Then
GraphicsWindow.Title = "Match Game - 1 Player, "
If (PlayAlone) Then
GraphicsWindow.Title = GraphicsWindow.Title + "Play Alone"
Else
GraphicsWindow.Title = GraphicsWindow.Title + "Play Computer"
EndIf
Else
GraphicsWindow.Title = "Match Game - 2 Players"
EndIf
EndSub
Controls.ButtonClicked = ButtonClickedSub
Sub ButtonClickedSub
B = Controls.LastClickedButton
If (GameStatus = "Stopped") Then
If (B = ExitButton) Then
Program.End()
ElseIf (B = OptionsButton) Then
SetOptions()
ElseIf (B = StartStopButton) Then
StartGame()
EndIf
ElseIf (GameStatus = "Playing") Then
If (B = StartStopButton) Then
'stop program
Message = "Game Stopped"
MessageX = 30
StopGame()
EndIf
EndIf
EndSub
Sub SetOptions
GraphicsWindow.Hide()
TextWindow.Show()
TextWindow.Title = "Match Game"
TextWindow.CursorLeft = 3
TextWindow.CursorTop = 3
TextWindow.WriteLine("MATCH GAME OPTIONS")
TextWindow.WriteLine("")
GetPlayers:
TextWindow.CursorLeft = 3
TextWindow.WriteLine("With one player, you play alone or against the computer.")
TextWindow.CursorLeft = 3
TextWindow.WriteLine("With two players, you play against a friend.")
TextWindow.CursorLeft = 3
TextWindow.Write("How many players do you want (1 or 2)? ")
NumberPlayers = TextWindow.ReadNumber()
If (NumberPlayers < 1 Or NumberPlayers > 2) Then
Goto GetPlayers
EndIf
If (NumberPlayers = 1) Then
Heading[1] = "You"
GetPlayAlone:
TextWindow.WriteLine("")
TextWindow.CursorLeft = 3
TextWindow.WriteLine("You can play alone or play the computer.")
TextWindow.CursorLeft = 3
TextWindow.Write("Make your choice (1-Play Alone, 2-Play Computer)? ")
T = TextWindow.ReadNumber()
If (T < 1 Or T > 2) Then
Goto GetPlayAlone
EndIf
If (T = 1) Then
PlayAlone = "true"
Heading[2] = "Guesses"
Else
PlayAlone = "false"
Heading[2] = "Computer"
GetDifficulty:
TextWindow.WriteLine("")
TextWindow.CursorLeft = 3
TextWindow.WriteLine("You can set the game difficulty.")
TextWindow.CursorLeft = 3
TextWindow.Write("Make your choice (1-Easiest, 2-Easy, 3-Hard, 4-Hardest)? ")
Difficulty = TextWindow.ReadNumber()
If (Difficulty < 1 Or Difficulty > 4) Then
Goto GetDifficulty
EndIf
EndIf
Else
Heading[1] = "Player 1"
Heading[2] = "Player 2"
EndIf
SetTitle()
TextWindow.Hide()
GraphicsWindow.Show()
EndSub
GameStatus = "Stopped"
For I = 1 To 10
GraphicsWindow.DrawResizedImage(Photo[I], BoxX[I], BoxY[I], BoxW, BoxH)
EndFor
Sub NRandomIntegers
'Order all elements initially
For I = 1 To N
NIntegers[I] = I
EndFor
'J is the number of integers remaining
For J = N To 2 Step -1
I = Math.GetRandomNumber(J)
T = NIntegers[J]
NIntegers[J] = NIntegers[I]
NIntegers[I] = T
EndFor
EndSub
N = 20
NRandomIntegers()
PhotoIndex = NIntegers
For I = 1 To 20
If (PhotoIndex[I] > 10) Then
PhotoIndex[I] = PhotoIndex[I] - 10
EndIf
EndFor
GraphicsWindow.DrawResizedImage(Photo[PhotoIndex[I]], BoxX[I], BoxY[I], BoxW, BoxH)
Sub KeyDownSub
K = Text.ConvertToUpperCase(GraphicsWindow.LastKey)
If (GameStatus = "Stopped") Then
If (K = "E") Then
Program.End()
ElseIf (K = "C") Then
SetOptions()
ElseIf (K = "S") Then
StartGame()
EndIf
EndIf
EndSub
Sub StartGame
GameStatus = "Playing"
'clear screen
GraphicsWindow.BrushColor = GraphicsWindow.BackgroundColor
GraphicsWindow.FillRectangle(0, 0, 625, 530)
Score[1] = 0
Score[2] = 0
PhotosRemaining = 20
N = 20
NRandomIntegers()
PhotoIndex = NIntegers
For I = 1 To 20
If (PhotoIndex[I] > 10) Then
PhotoIndex[I] = PhotoIndex[I] - 10
EndIf
PhotoFound[I] = "false"
GraphicsWindow.DrawResizedImage(Cover, BoxX[I], BoxY[I], BoxW, BoxH)
EndFor
PlayerNumber = 1
ChoiceNumber = 1
If (NumberPlayers = 1) Then
Message = "Pick a Box"
MessageX = 45
Else
Message = "Player 1, Pick a Box"
MessageX = 10
EndIf
DisplayMessage()
'reset buttons
GraphicsWindow.BrushColor = "Black"
GraphicsWindow.FontSize = 16
Controls.SetButtonCaption(StartStopButton, "Stop Game")
Controls.HideControl(OptionsButton)
Controls.HideControl(ExitButton)
CanClick = "true"
EndSub
Sub StopGame
'restore buttons
GameStatus = "Stopped"
GraphicsWindow.BrushColor = "Black"
GraphicsWindow.FontSize = 16
Controls.SetButtonCaption(StartStopButton, "Start Game")
Controls.ShowControl(OptionsButton)
Controls.ShowControl(ExitButton)
CanClick = "false"
DisplayMessage()
EndSub
Sub ShowPhotoAndCheck
'show image behind selected Photo box (BoxNumber)
GraphicsWindow.DrawResizedImage(Photo[PhotoIndex[BoxNumber]], BoxX[BoxNumber], BoxY[BoxNumber], BoxW, BoxH)
PhotoFound[BoxNumber] = "true"
If (ChoiceNumber = 1) Then
Choice[1] = BoxNumber
ChoiceNumber = 2
If (NumberPlayers = 2) Then
Message = "Player " + PlayerNumber + ", Pick Another"
MessageX = 5
DisplayMessage()
Else
'one player logic
EndIf
Else
CanClick = "false"
Timer.Resume()
EndIf
EndSub
Sub TickSub
Choice[2] = BoxNumber
ChoiceNumber = 1
If (PhotoIndex[Choice[1]] = PhotoIndex[Choice[2]]) Then
'a match
Sound.Stop(Program.Directory + "\tada.wav")
Sound.PlayAndWait(Program.Directory + "\tada.wav")
'blank out boxes
GraphicsWindow.BrushColor = "White"
GraphicsWindow.FillRectangle(BoxX[Choice[1]], BoxY[Choice[1]], BoxW, BoxH)
GraphicsWindow.FillRectangle(BoxX[Choice[2]], BoxY[Choice[2]], BoxW, BoxH)
Score[PlayerNumber] = Score[PlayerNumber] + 1
PhotosRemaining = PhotosRemaining - 2
If (PhotosRemaining = 0) Then
Sound.Stop(Program.Directory + "\wow.wav")
Sound.Play(Program.Directory + "\wow.wav")
If (NumberPlayers = 2) Then
If (Score[1] > Score[2]) Then
Message = "Player 1 Wins!"
MessageX = 30
ElseIf (Score[2] > Score[1]) Then
Message = "Player 2 Wins!"
MessageX = 30
Else
Message = "It's a Tie!"
MessageX = 45
EndIf
Else
'one player logic
EndIf
StopGame()
EndIf
'another turn?
If (PhotosRemaining <> 0) Then
If (NumberPlayers = 2) Then
Message = "Player " + PlayerNumber + ", Pick Again"
MessageX = 10
DisplayMessage()
Else
'one player logic
EndIf
EndIf
Else
'no match
Sound.Stop(Program.Directory + "\boing.wav")
Sound.PlayAndWait(Program.Directory + "\boing.wav")
PhotoFound[Choice[1]] = "false"
PhotoFound[Choice[2]] = "false"
GraphicsWindow.DrawResizedImage(Cover, BoxX[Choice[1]], BoxY[Choice[1]], BoxW, BoxH)
GraphicsWindow.DrawResizedImage(Cover, BoxX[Choice[2]], BoxY[Choice[2]], BoxW, BoxH)
'swap players
If (NumberPlayers = 2) Then
If (PlayerNumber = 1) Then
PlayerNumber = 2
Else
PlayerNumber = 1
EndIf
Message = "Player " + PlayerNumber + ", Pick a Box"
MessageX = 10
DisplayMessage()
Else
'one player logic
EndIf
EndIf
CanClick = "true"
EndSub

Answer 1

To debug this we need to do a couple of things which are common to most debugging problems.
1] Add TextWindow.WriteLine statements in lots of places to see exactly where the problem occurs - this will help to write the simple test code to show the issue.  Start by one in the start and end of each Subroutine for example, then add more to identify
the line at which the problem occurs.
Then, if the issue is not clear:
2] Simplify the code as much as possible to show the error - i.e write a simple test program or start from your program and delete bits that are not relevant to your problem.  If you don't need images or sounds in other files to show the problem then
remove them so that some-one else can run the file and see the problem.  If extra images or files are needed to show it, then use test web files, again so the program can be run by some-one else.
Once you do this we can see that the issue is with Sound.Stop().
And a simple test file:
musicFile = "http://litdev.co.uk/game_images/backgroundMusic.mp3"
Sound.Play(musicFile)
Timer.Interval = 5000
Timer.Tick = OnTick
Sub OnTick
Sound.Stop(musicFile)
EndSub
So the problem is that we cannot act on the music with Sound commands from inside an event subroutine - they work on a separate thread to the main UI thread.
Solution: do all work on the main UI thread and only use the event subroutines to set flags:
musicFile = "http://litdev.co.uk/game_images/backgroundMusic.mp3"
Sound.Play(musicFile)
Timer.Interval = 5000
Timer.Tick = OnTick
While ("True")
If (restartMusic) Then
Sound.Stop(musicFile)
Program.Delay(100) 'To hear restart
Sound.Play(musicFile)
restartMusic = "False"
EndIf
Program.Delay(20) 'Don't mash cpu while waiting for input in game loop
EndWhile
Sub OnTick
restartMusic = "True" 'Flag that the music should restart
EndSub
Or more moduar:
musicFile = "http://litdev.co.uk/game_images/backgroundMusic.mp3"
Sound.Play(musicFile)
Timer.Interval = 5000
Timer.Tick = OnTick
While ("True")
CheckRestart()
Program.Delay(20)
EndWhile
Sub OnTick
restartMusic = "True"
EndSub
Sub CheckRestart
If (restartMusic) Then
Sound.Stop(musicFile)
Program.Delay(100) 'To hear restart
Sound.Play(musicFile)
restartMusic = "False"
EndIf
EndSub
For more info see the following wiki articles
http://social.technet.microsoft.com/wiki/contents/articles/15060.small-basic-event-basics.aspx
http://social.technet.microsoft.com/wiki/contents/articles/22264.small-basic-threading.aspx
and for the game loop (While )"True" loop
http://social.technet.microsoft.com/wiki/contents/articles/20865.small-basic-dynamic-graphics.aspx
PS nice program interface by the way - the game loop and event flags is the best way in Small Basic and often in other languages - good luck