IMac trouble opening certain programs

Question

problem is: i will try to open certain programs, they will quickly appear in the dock, and then the icon will fade away without ever opening the program.
this particular problem began a little over a year ago when i upgraded to tiger. i was running pro tools frequently at the time, and did not realize that my pro tools program would not be compatible with the new OS. so i downgraded back to 10.3.9, and that's when this particular problem began.
i knew there would be consequences to my downgrade like this. my printer no longer interfaced with my computer, safari no longer opened, etc. and i dealt with it. however, i got a strange message yesterday when i went to open a .txt file saying "this is the first time you've used the program Text Edit", and then i got it again a few minutes ago when i tried to open System Preferences ("this is the first time you've used the program System Preferences"). now for the first time ever, my System Preferences will not open.
my most recent actions have been updating iChat A/V, updating Limewire, messing with some .bin files, and it says my "AppleScript" was modified last night around the time i got the message about Text Edit (which is odd because i've never used AppleScript).
iMac G4   Mac OS X (10.3.9)  

Answer 1

If you think a corrupted preference file may be the cause, you can run a quick command line in Terminal to diagnose any troublesome ones. If it shows any corrupted prefs files, then you can delete only those, then restart.
Open Utilities>Terminal
enter:
plutil -s ~/Library/Preferences/*.plist <enter>
This checks for corrupted prefs files in your home folder. If there are any, it will display the file's path. Just delete that file and reboot. If nothing is displayed, then everything checked out okay.
You should also check prefs files OUTside of your home folder by omitting the tilde "~" in the terminal command. Like so:
plutil -s /Library/Preferences/*.plist <enter>
Again, bad prefs files will show, otherwise you get nothing.
This may not help your problem if it's not prefs related, but couldn't hurt nonetheless.
iMac 20" 2GHz Intel Core Duo   Mac OS X (10.4.4)   iBook G3 Dual USB 640MB 30GB -- Two iMac SE DVs
iMac 20" 2GHz Intel Core Duo   Mac OS X (10.4.6)   iBook G3 Dual USB 640MB 30GB -- Two iMac SE DVs