One useful tool in troubleshooting an AD RMS issue on the client is tracing. All that is needed is a tool from Sysinternals, a registry change, and reproduce the issue.
Steps: (x64 Windows 7 with x86 Office 2010 used in the screenshots)
The DRM specific output is prefaced with [msdrm] in the DebugView output.
NOTE: for the RMS 2.0 Client (AKA MSIPC) the registry key will be MSIPC instead of MSDRM. For example: