Did you change to a new printer or upgrade FileMaker?
Sounds like a known issue with Mac systems and some printers:
For More Information see: FM 11 Print all records
This is one of many acknowledged bugs that can be found in the Known Bug List here in the Report an Issue section of the forum.
It can also be downloaded as a database file from: http://www.4shared.com/file/8orL8apk/FMP_Bugs.html
Nothing has changed that I know of except Filemaker behavior. Same Filemaker, same printer, Same computer, no OS upgrade except for normal Snow Leopard periodic updates. All other programs behaving normally.