Apple Logic Pro /LogicExpress Discussion

Hi folks,

I get the following error message whwn I try to freeze my softsynth tracks:
"Attempt to position before start of file
result code = -40"

Consequently, the freeze audio will not be created (even though Logic treats the the track 
as frozen for any editing operations) and processing power at playback is not optimized.

Any idea what's wrong?

Thanks,
Michael