Had this recently in an SCCM 2007 environment. After a bit of poking around I decided to reinstall the management point but this failed to fix the problem. Looking in the MPSetup.log is the error:
Fatal MSI Error – mp.msi could not be installed
After ensuring all the WebDAV setting were correct I started to scratch my head a bit before seeing one or two forum entries which suggested fairly major surgery but crucially included the step to run CCMClean. Well, this did make me think and I checked the SCCM client on the primary site. This was a lab environment and there was an overlapping boundary which caused a CM2012 client to be installed on this box.
I simply removed this client, removed and reinstalled the MP and everything was fine.