n3u,

I'm afraid I have to echo Scott's sentiment that I don't know what else to add, other than to be sure you are replicating the manual steps accurately and that your code is clean. I've seen crashes before that were my fault but didn't show up until later in the processing. It's possible that you have violated the integrity of the memory somewhere but it doesn't get "stepped on" until Frame does the PDF step. Be sure that you have allocated and deallocated everything carefully.

Russ