Most seemed to have no trouble, but yes, there have been a few who noted odd glitches after upgrading to Panther. Here are two suggestions.

The first is to do a safe boot (restart and hold down the shift key just after the startup chime), then use the Disk Utility in the Utilities folder to repair Permissions
Click here for the detailed links. The folks on the Apple discussion forums recommend this before and after any update anyway. Restart and if all is well, great.

If that doesn't work, try a clean install. Search your hard drive for all files containing "limew" to find all the old pieces, and move them to the trash. Download a fresh version and try again. To really start fresh, also clean out your Shared folder, then delete it and the Incomplete folder.

Cheers