Issues with creating shared PDFs in Acrobat Pro 11

We're having issues with shared PDFs that are created in Acrobat Pro 11.0.11 or above.

When some users create shared PDFs and send them for shared review, they can be viewed as shared PDFs in Acrobat Pro (yellow bar appears, with shared PDF functions), but not in Adobe Reader 11.0.11 or above (no shared review menu bar appears, nor can we seem to display it manually).

Does anyone know what could be wrong? This is only for PDFs created by some users, other shared review PDFs created with Acrobat Pro 11.0.11 or above open just fine in Reader 11.0.11 or above. I'm thinking it might be a setting that is not correct for some users...

Thanks!!

Paul Masalsky

McAfee (now part of Intel Security)