Some PDF attachments are not downloading fully, sometimes freeze

Hi,

I've been using Presenter for several years now and have run into an issue that I never had before. For each presentation, I add a PDF attachment. On my latest set of presentations (about 12 of them), some of the PDFs will open fine but others will not. The download meter stops about 1/5 of the way in and I just see a black page. This is in Firefox 6. When I do the same steps in Internet Explorer, it freezes the browser. I'm viewing these from the server, so local permissions are not the problem. The filenames are fine.

I've also tried creating the PDF via different methods -- via the Print dialog box as well as via the Create PDF command under the Acrobat tab. It actually seemed to fix one of the presentations, so I thought that was the answer. But, then I tried another one and it didn't help it. So I'm perplexed.

Has anybody else had this issue? Are there known issues with different PDF flavors in attachments?

Thanks for any help you can give,

Becky