I publish this error as its cause was really weird:
I was getting an error when trying to start any Management Console related program (mmc.exe based admin tool), like Certificates, Event Viewer, etc.
The error was:
“The application has failed to start because its side-by-side configuration is incorrect.
Just a tip I always have to do when setting up a Windows Server 2008 VPC (Virtual PC) which is also a DC (Active Directory Domain Controller).
As those machines are just for demos or development environment, I do not want to have the Domain account policies which are quite strict,