tell application "Finder"
  --This is where you put the path to the compiled fixid3tag
  set FixerLocation to "~/Documents/fixid3tag"
  --This is the path to your temporary folder
  set FixedFolder to (folder "Fixed" in desktop) as alias
end tell

tell application "iTunes"
  set trackList to the selection of window 1 
  repeat with theTrack in trackList
    set theTrackName to ((the location of theTrack))
    do shell script FixerLocation & " " & quoted form of POSIX path of theTrackName
    do shell script "cp " & quoted form of POSIX path of theTrackName & " " & quoted form of POSIX path of FixedFolder
    delete theTrack
    do shell script "rm " & quoted form of POSIX path of theTrackName
  end repeat
end tell

--add fixed files to iTunes
tell application "Finder"
  set theseFiles to (files of folder FixedFolder as alias list)
end tell
try
  tell application "iTunes" to add theseFiles
on error err
end try

--delete converted temp files
tell application "Finder"
  delete every item of folder FixedFolder
end tell