Big Ask For Help.

Question

I have been writing what i consider to a big project, as it is my first real attempt at writing something useful for myself. However i have got to a point where i cant really see why it isnt working. I had it working and changed something saved it and now it wont work. I am using this plug in to get the Key Pressed.
http://osaxen.com/files/jonscommandsx3.0d3.html
Basically, i am writing a program to sit in my dock and organize files i drop onto it. I have set up the preferences so it remembers which letter is assigned to which shortcut. I have tried to cover all the possibilities, but i have gotten lost somewhere along the way.
So if someone would be so kind as to have a quick read and give me a pointer as to why it doesnt work that would be great.
Code Begins Below:
on open (droppedFiles)
tell application "Finder"
activate
set letterlist to (do shell script "/usr/bin/defaults read com.Rich.move letterlist")
set theKeyPressed to ""
repeat until theKeyPressed is not ""
set theKeyPressed to (keys pressed) as string
if theKeyPressed is equal to "J" then
my newloc
my newassign
my addcomments
my movefiles
else if letterlist does not contain theKeyPressed then
display dialog " Key Not Assigned"
my newloc
else
my addcomments
my movefiles
end if
end repeat
end tell
end open
on deleteassign(theKeyPressed, letterlist, theLetter)
-- do shell script "/usr/bin/defaults write com.Rich.move " & theLetter & "text" & " "
set letterlist to (do shell script "/usr/bin/defaults read com.Rich.move letterlist")
set theLetter to "p"
if letterlist contains theLetter then
set {templist, letterlist} to {letterlist, {}}
repeat with a_letter in templist
tell a_letter's contents to if it is not theLetter then copy it to the end of letterlist
do shell script "/usr/bin/defaults write com.Rich.move letterlist " & (letterlist as string)
end repeat
end if
return letterlist
end deleteassign
on addcomments(droppedFiles, letterlist, theKeyPressed, theLetter)
repeat with each_item in droppedFiles
set the_comments to quoted form of (do shell script "/usr/bin/defaults read com.Rich.move " & theKeyPressed & "Text")
tell application "Finder"
set comment of alias each_item to text of the_comments
end tell
end repeat
end addcomments
on newloc(theKeyPressed, droppedFiles, letterlist)
set newmove to choose folder with prompt "Move To Here"
set newmove1 to quoted form of (POSIX path of (newmove as string))
set theLetter to the text returned of (display dialog "Assign Letter" default answer "…")
set textofcomments to the text returned of (display dialog "Add Metadata" default answer "…")
do shell script "/usr/bin/defaults write com.Rich.move " & theLetter & " " & (newmove1 as string)
do shell script "/usr/bin/defaults write com.Rich.move " & theLetter & "Text" & " " & (textofcomments as string)
end newloc
on newassign(letterlist, theKeyPressed)
if letterlist does not contain theKeyPressed then
copy (theKeyPressed) to end of letterlist
do shell script "/usr/bin/defaults write com.Rich.move letterlist " & (letterlist as string)
else
set {theLetter, thebutton} to {the text returned, the button returned} of (display dialog "Already Assigned!" & return & "Please assign a new letter" default answer "…" buttons {"Cancel", "Delete Previous Location for this Letter", "OK"} default button "OK")
if theLetter is equal to "J" then
display dialog "You can not choose J, please try again"
my newassign
else if button returned is "Delete Previous Location for this Letter" then
my deleteassign
my newassign
else
my newassign
end if
end if
end newassign
on movefiles(theKeyPressed, droppedFiles, letterlist)
repeat with each_item in droppedFiles
set each_item1 to quoted form of (POSIX path of (each_item as string))
set _path to quoted form of (do shell script "/usr/bin/defaults read com.Rich.move " & theKeyPressed)
display dialog _path
do shell script ("ditto -rsrc " & each_item1 & " " & _path)
do shell script ("rm " & each_item)
end repeat
end movefiles

Answer 1

Debugging droplets is no fun when all you've got is an 'on open' handler. The first thing I suggest you do is to move all that code in the 'on open' handler to a new, separate handler that you can call from both the 'on open' and an 'on run' handler. That way you can do all your debugging in Script Editor, which will help locate precisely where the script is failing.
click here to open this script in your editor<pre style="font-family: 'Monaco', 'Courier New', Courier, monospace; overflow:auto; color: #222; background: #DDD; padding: 0.2em; font-size: 10px; width:400px">on open droppedFiles
main_scpt(first item of droppedFiles)
end open
on run
"/Applications/TextEdit.app" -- any test file
main_scpt(POSIX file result)
end run
on main_scpt(droppedFiles)
display dialog droppedFiles as string
(* Your script goes here *)
end main_scpt
</pre>I agree with Cyclo's comments that you need to make sure your subroutine (function/handler/whatever) calls match precisely the parameters of the subroutines themselves. It's important to make sure all the values you're sending have been declared (set to something) in advance. Note that the parameters you're passing are also positional. This means they must all line up in the same order in both the call and the function. (It's not smart enough to know that letterlist = letterlist, only that 2nd parameter = 2nd parameter)
Now, if you want to be lazy you can dispense with all this rampant parameter slinging and simply declare all your variables as globals. To do that write the word 'global' at the very top of your script, followed by all the variable names you want to be shared among your subroutines, e.g.
global droppedFiles, letterlist, theKeyPressed, theLetter
…so on and so forth. Once you've done this it's no longer necessary to pass these parameters, but you must still use the '()' empty parenthesis at the end of all your function calls so AppleScript knows it's a call and not just an ordinary variable.