After I got an error about an missing envdte.dll or invald signature. I put the right envdte.dll into private assemblies folder, and since then resharper works like a charm, no more exceptions no not found classes.
On my machine I have Visual Studio version 2003 and visual studio version 2005 installed and i saw that two versions of envdte exist one for 2003 and one for 2005, maybe this caused a lot of problems.
C:\Program Files\Microsoft Visual Studio .NET 2003\Common7\IDE\PrivateAssemblies
Is the folder where I put the dll. I currently only use the resharper version for visual studio 2003