Hi Marius,

 

This sounds an lot like the thread below (ignore the posts up until March 4th of 2010):

http://channel9.msdn.com/forums/TechOff/22266-Side-by-side-screwup/#Page=2

 

A recent Hotfix was released by MS, which could mean that your build-machine is trying to reference a DLL that won't be on your customer's machines.  Maybe it's the same thing, maybe not. But, it sure sounds like it could be related.

 

-tom