FairUse4WM is not compatible with IBX 11.0.6000.6324. See the following thread for more:
FairUse4WM Errors
the newest version of drmdbg works with IBX 11.0.6000.6324 and FairUse4WM 1.4 should support it as well. As soon as it is released I will post about it.
How to use drmdbg.exe 
1. Run drmdbg.exe 
2. When your Windows Media Player (WMP) opens, add a DRM-protected file to the playlist and tell WMP to start playing. 
3. A dialog will pop-up with the KID for the SID, and the KID will also be saved to the key file needed to run drm2wmv.