Strange error in BizTalk mapping

I creat开发者_如何学运维ed a map in Biztalk and tried to compile the project with it (project contains only this map).

But I have this compilation error:

Error 1 Exception Caught: Method not found: 'Microsoft.BizTalk.TOM.ITOMTree Microsoft.BizTalk.Mapper.OM.Map.get_TargetTree()'.

I added a reference to Microsoft.BizTalk.TOM and Microsoft.BizTalk.Mapper.OM, but this doesn't help.

Try re-registering the Microsoft.BizTalk.TOM assembly to the GAC, re-open project and try again.