How are you running FRED with parallels? I've tried it, and it always crashes for me. Would you mind explaining how you've got things set up? 
Well, I'm using Parallels Desktop 4.0 for Mac, running Windows XP Service Pack 3. I have FRED2 3.6.10 revision 5063. Umm, I believe I have Parallels using 1236 MB of my available 2gigs of RAM.
All I did to get it running, was install FS2 retail, then FSO as you normally would on a Windows machine. However, it doesn't run perfectly. It runs real choppy in Coherence and also if I have it open for over an hour it starts getting very slow, and also whenever I close it, I get an error.
Need any more details just ask.

I'll do my best to help troubleshoot.
What sort of error are you getting when you try to run it?