Adobe Reader 10.0 is installed in a protected mode. One of the features of the secure mode is:

  • Cannot open PDF files whose source is DFS or NFS: PDF files in shared locations on a distributed  or networked file system (DFS/NFS) cannot be opened. Attempting to open such a file results in an error opening this document. Access denied."

The solution is to disable protected mode by completing the following steps: [more]

  1. Within Adobe Reader, go to Edit > Preferences > General and deselect Enable Protected Mode at startup.
  2. Restart Reader.

For more information, refer to the following Adobe KB article: