If you face problems with FrameMaker 7/8 suddenly crashing when you try to generate PDF files, you’re probably missing a hotfix that Microsoft has released for FrameMaker. This hotfix solves some other issues as well.
Try these links:
A related blog post on the Adobe Technical Communication blog is here.
It’s a pity that there is no patch for Windows 7 available as I encounter the very same problem from time to time.