From: Harold on
I have several 2005 SQL Projects saved in Visual Source Safe and when I try
to open with SSMS 2008 R2, I get a Class Not Registered error.

I went under tools>options to make sure things looked right there.

I have received two different error.
1) Class not registered
2) The located assembly manifest definition does not match the assembly

I also tried adding a new SQL project and it did nothing.