Thank you for your post.
Can you provide any other information about your system? That is, what other applications are running? Do you have any plug-ins installed?
Do you have access to another Snow Leopard machine? If so, can you see if you encounter the same behavior?
Any additional information you can provide may be helpful in determining possible cause(s).
Typically, other running apps would include Mail, Firefox, SnapTalk, AddressBook and iCal. There are no FM plug-ins, to my knowledge. And no, I don't have access to any other machine running Snow Leopard. Sorry.
I'm not having any luck replicating the problem on my Snow Leopard machine. I am running Mail, Address Book, iCal and Safari. I don't have SnapTalk. I have closed all files, disconnected from the network, reconnected, and I'm still able to open and access remote files.
In case FileMaker Pro has somehow become corrupt, I would uninstall FileMaker Pro and reinstall. If that fails, then I would reinstall Snow Leopard from the CD, reinstall FileMaker Pro, and try again. Other than that, I'm out of options.
Anybody else having trouble with FileMaker hanging after disconnecting from the network?