The inline document viewer appears drastically different than the standard Jive theme, and in some browsers throws an error stating that access is denied to /flash/conversion/viewer.swf.
Either a proxy or SSO system is blocking the browser's access to the required flash assets. You can test this by obtaining a fiddler capture of the transaction. Note the response from the server when /flash/conversion/viewer.swf is requested.
You will need to configure your SSO system to allow the following request without authentication: