This could be a .NET directory ownership problem.

Solution:

1.

navigate to c:\windows\microsoft.net then right click the assembly folder and click properties...
2. go to the security tab
3. click advanced near the bottom
4. in the new window go to the owner tab
5. at the bottom click edit
6. then click your user name (since you should be an administrator)
7. check REPLACE OWNER ON SUBCONTAINERS AND OBJECTS
8. click apply
9. click ok
10. accept any popups (usually saying you have to close the properties tab)
11.  then just keep hitting ok