Just add a symbol server that serves more then just major releases.
Try this one, contains most minor builds.
http://srv.symbolsource.org/pdb/Public
Verify:
Run VS as administrator.
Check that something have been downloaded to your symbol cache directory.
Goto select only specified modules.
Add “System.Web.Mvc.dll”
Set a break point in your code. Start debug.
When break point hits rightclick in callstack on any mvc.dll row. Verify that symbols are loaded.
if loaded, try dubbleclick on one callstack row to open mvc source.
Get back with where you get in trouble.