If you have spent any length of time working with BizTalk server 2009, chances are you’ve probably come across number of issues with Visual Studio 2008 integration. For instance, project references between BizTalk projects raises unexplainable design-time errors in your orchestration files. These errors sometimes go away mysteriously if you recompile or resave associated files. Very annoying stuff indeed. It turns out Microsoft has released a hotfix for many of these issues.
http://support.microsoft.com/kb/977428/en-us
If you are having issues within Visual Studio 2008, you might want to give this a try.
