The files may be damaged, as the message states. This can happen lots of ways - could be a corrupt preference, could be another application install.
Have you loaded ANY software updates, etc. in the last 4 weeks? had a crash of your computer? etc?
So - many things can corrupt a file - hard to tell exactly why it stopped working. Have you tested the script on another computer? That may tell you if its a problem with the script or with the computer. My guess is that it will work on a different computer, so it's not a script problem.
If it's the computer/install - as you are on a Mac - you can try a few things -
Use Disk Utility to repair permissions and verify the disk.
Then uninstall and reinstall FM11 on that machine.
Uninstall is just a delete of the application folder (be sure to back up any plug-ins first) and be sure to delete the preference files from the system folder (if you are on Lion, those may be hidden in your personal user Library - hold down the option key and choose Go menu in the Finder, and you will see an option for Library - look for com.filemaker.something in the preferences folder.).
Reinstall and test again. Let us know what works.
Thanks Karen, once again.
I tried it on other computers and its my computer that it breaks down on. I'll follow your suggestions.