[hotwheels]

See if this help's, go to your user admincp, and scroll down to attachments and open that, then click on attachment permissions.
Now you will see the document permission types, doc, pdf, etc....and then you will see the admin, moderators, users, etc.......choose say pdf and select admin, select use custom permissions, then change the 20000, to what ever number you want, like 20000000, and click save.

Try to reupload your pdf file.......