Fedora :: Cannot Downgrade Glibmm - VMware Not Running

I'm running Fedora 15 x86_64 on a Dell Latitude E6500. VMware Workstation won't run if I have glibmm24-2.28.1-1.fc15.x86_64 installed. I managed to downgrade to glibmm24-2.24.2-1.fc14.1.x86_64, and VMWare Workstation worked. Then, I did a "yum upgrade". Now vmware won't run. I tried to downgrade glibmm back to the 24-2.24 version, but I get the message:

Code:
% yum downgrade glibmm24-2.24.2-1.fc14.1.x86_64.rpm
Loaded plugins: auto-update-debuginfo, presto, refresh-packagekit
Setting up Downgrade Process
Examining glibmm24-2.24.2-1.fc14.1.x86_64.rpm: glibmm24-2.24.2-1.fc14.1.x86_64
Resolving Dependencies
--> Running transaction check
---> Package glibmm24.x86_64 0:2.24.2-1.fc14.1 will be a downgrade
---> Package glibmm24.x86_64 0:2.28.1-1.fc15 will be erased
--> Finished Dependency Resolution
Error: Protected multilib versions: glibmm24-2.24.2-1.fc14.1.x86_64 != glibmm24-2.28.1-1.fc15.i686
You could try using --skip-broken to work around the problem
** Found 1 pre-existing rpmdb problem(s), 'yum check' output follows:
autopano-sift-C-3.5.1-1.fc12.x86_64 has missing requires of libpano13.so.1()(64bit)
So I added the --skip-broken flag .....