After upgrading the Adobe Reader to version 10.1.0 for a customer, some users began to see prompts for accepting the EULA. This seemed to be pretty random because not all PDF files were causing the behavior. I did a quick Google search and found the following link:
http://patrickhoban.wordpress.com/2011/07/09/124/
Apparently if you have the letter "CR" (must be in this order, capitalized and together) in the file name it will trigger this behavior. The link above explains what registry key is missing and how to fix the problem.