It could be alot of things, though you didn't give any details on what kind of iPhone your running or the os version. It could be the pdf files are too large, or it could be that all the pdf files haven't been downloaded yet before you try to send them.pdf files naturally take longer than other files to show up, think its because of their compression.
To eliminate or isolate your issue I would start with say, 2 pdf files test from there and continue to go up sending more and more untill you see whats going on.
11-18-2010 12:47 PM