There are some simple troubleshooting steps you can take.
Be sure you drive is not overly full. Rule of thumb would be over 85%.
Create a new User go to System Preferences >> Accounts >> "+" (make it an admin acct) and test the apps in this new account, if they work the problem is isolated to your User and not systemwide.
If the issue is limited to your user account try starting up
Safe Mode (It will take more time to startup in Safe Mode because it runs a directory check.)
If your apps functions correctly that way, go to System Preferences >> Accounts >>
Login Items, and remove them. Boot normally and test. If not go to/Users/yourname/Library
/Contextual Menu Items and move whatever is there to the desktop. Then do the same with /Library/
Contextual Menu Items. Lastly, try moving/Users/yourname/Library/
Fonts to your desktop and restarting.
Log out/in or restart, if that sorts it start putting items back one at a time until you find the culprit.
If the issue is systemwide then, you may be able to repair this with the
The 10.6.4 Combo Update This is a fuller install, as opposed to an incremental "delta" update so it should overwrite any files that are damaged or missing. It does not matter if you have applied it before.
Remember to Verify Disk before update and repair permissions after update from /Applications/Utilities/Disk Utility.
-mj