I have recently tried upgrading from VSC 2.0.1 to 2.1. This is on an IBM nSeries running vSphere 4.1. The upgrade states it has been successful but under Monitoring and Host Configuration the Update feature does not work. Under About it strangely reports that all the components have been updated but the version of VSC remains on 2.0.1. After trying to use the upgrade feature I have then uninstalled and reinstalled the product but this has the same effect.
I have a second Virtual Centre at a separate site and the upgrade there worked without issue despite there being no obvious difference in the configs.
One last note this is Server 2008R2 (hence 64 bit)