Delimiters may be the cuprit

Question

the text for display dialog with title 2 will not produce any text that will display. I think its due to the delimiters that break apart the file name and not be reset properly. Can anyone lend a hand thanks. This code is taken from Applescript Studio.
on clicked theObject
tell application "Finder"
set the_alphabet to {"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"}
set NPR_local to "Macintosh HD:Users:Shawn:Desktop" -- :DAW1:Features"
set theSelection to get selection -- the highlighted file in the Finder window "Macintosh HD:User:Shawn:Desktop:DAW:AR999 Smith, Bob EM v1.mov"
set theprodinitials to ""
set theprojectfolder to ""
set theprojectname to ""
set thebackuplocation to "Masters:Features:Archive - Features"
set file_name to ""
end tell
--thefilename AR999 Smith, Bob EM v1.mov
tell application "Finder"
--display dialog theSelection as string
--display dialog "1 " & a_file as string -- "Macintosh HD:Users:Shawn:Desktop:Featurs Folder:AR999 Smith, Bob:AR999 v2.mov"
set TempTID to AppleScript's text item delimiters -- save the current delimiter
set AppleScript's text item delimiters to ":" -- the text to replace
set thefilename to the last text item of (theSelection as string) -- "AR999 Smith, Bob EM v2.mov"
set AppleScript's text item delimiters to ""
display dialog thefilename with title "1"
end tell
--theprojectname AR999 Smith, Bob
tell application "Finder"
set TempTID to AppleScript's text item delimiters -- save the current delimiter
set AppleScript's text item delimiters to " " -- the text to replace
set theprojectname to text items 1 thru -3 of (thefilename as string) -- "AR999 Smith, John"
set AppleScript's text item delimiters to TempTID -- restore the original delimiter
display dialog theprojectname with title "2"
end tell
-- theprojectcode AR999
tell application "Finder"
set AppleScript's text item delimiters to " " -- the text to replace
set theprojectcode to text item 1 of theprojectname -- AR999
set AppleScript's text item delimiters to {""}
display dialog theprojectname with title "3"
end tell
-- Prod initials "– AR"
tell application "Finder"
repeat with a_character in theprojectcode
if a_character is in the_alphabet then
set theprodinitials to theprodinitials & a_character
end if
end repeat
set theprodinitials to "- " & theprodinitials
set AppleScript's text item delimiters to {""} -- default delimiters
display dialog theprojectname with title "4"
end tell
-- get the Abraham NPR location
tell application "Finder"
set AppleScript's text item delimiters to {" "} -- default delimiters
repeat with aproducersfolder in folder thebackuplocation -- "Reid, Amy – AR" "Masters:Features:Archive - Features"
set x to name of aproducersfolder as string
if x contains theprodinitials then -- "– AR"
display dialog x as string with title "5"
--display dialog aproducersfolder as string with title "5 prod fold on abr"
set theprojectfolder to (aproducersfolder as string) & theprojectname as string
end if
end repeat
tell application "Finder" to duplicate (every folder of folder theprojectfolder whose name contains "NPR") to folder NPR_local
end tell
end clicked

Answer 1

Without running the code, it's hard to be sure, but you do seem to be all over the place with your TIDs:
For example, there are two places where you:
set TempTID to AppleScript's text item delimiters -- save the current delimiter
which is great - you're saving the current setting to restore later. However, there's only one place where you restore to that previously-saved value:
set AppleScript's text item delimiters to TempTID -- restore the original delimiter
In other places you:
set AppleScript's text item delimiters to ""
set AppleScript's text item delimiters to {""} -- default delimiters
set AppleScript's text item delimiters to {" "} -- default delimiters
I don't know if that's because you're trying out different options to see what works, or whether that an error, but it would be good to be consistent - always save the current TID, set a new value, then restore the old TID - in each stage rather than the hybrid model you have right now. If nothing else it would make it easier to spot other errors.