I'm testing Team Review on the virtual Team Foundation Server machine you can download from Microsoft.
The original machine had a complete VS2008 and a VS 2005 Team Explorer installed. To simulate the situation in our company, I installed VS 2005 C# and C++.
I imported the template. Adding a "code review response" via Team->Add Workitem works fine in both Visual Studios. In VS 2008 the addin works fine too, but in VS 2005 the addin always reports the same error as Balaji reported above.
I can check in and out, all the bindings to Team Foundation Server are fine.
I have no idea anymore :-)
Any help would be great!