Currently there is a incompatibility with the latest Source Engine (Source 2009), preventing the Mod to start up. As a temporary workaround do the following:
1. Run Steam
2. Enter the Game Library then select Tools.
3. Find and Install Source SDK, Source SDK Base 2006, and Source SDK Base 2007.
4. Restart Steam
A fully ported version of CM (V. 10.90) will be available with the release of VALVE's updated SDK.