FileMaker Version: 6
Platform: Mac OS X Panther
I've had the same problem with 5.5 Unlimited and now with 6.0 Unlimited on Mac OS X Server 10.3. I don't have any AppleScripts interacting with FileMaker at all.
It seems to freeze when there's any appreciable database activity. Most of our database access is via the Web Companion.
I placed a call to FileMaker Tech support. The tech (Justin, really nice, patient, and knowledgeable) had me check the CPU usage. It hovered around 97%-100%, so it was trying to do something.
Justin had me turn on all logging for Web Companion. I can call back with the data upon the next freeze. (I call this "failure-mode analysis, a la the AE-35 antenna positioning unit in "2001: A Space Odyssey" ;-)
I'll post back if/when I find out anything more.
++Steve