New Post: Failure removing assembly from cache: The parameter is incorrect.

To help debug it, you could paste the following into the .btdfproj file (on the server):
There are only two steps in UndeployOrchestrations -- one that opens the DLL(s) and reads the assembly information from each one, and another that runs GacUtil.exe. This target should print the assembly filenames into the BTDF output.

Double-check to make sure that the Orchestration DLL's are still present in the install folder on the server, because it can't undeploy without them (not in the GAC, in the Program Files folder for the app).

Thanks,
Tom