BlackBerry Client for use with Microsoft Office Communications Server 2007 known issues
If a BlackBerry® device user sends a message to an invalid contact, the error message "Failed to execute your last action" displays. The error message does not specify that the contact does not have a valid ID or that the contact might reside in an external domain. (SDR 303950)
In certain circumstances, the BlackBerry Collaboration Service experiences performance issues. (SDR 287243)
Workaround: Instruct users to log out of the BlackBerry® Client for use with Microsoft® Office Communications Server 2007 periodically.
When using Windows® NTLM authentication, an error occurs if two or more users try to log in to the BlackBerry Client for use with Microsoft Office Communications Server 2007, or if one user logs out, and then quickly logs in. (SDR 257764)
Workaround: Set up Kerberos™ authentication or force forms-based authentication.