RegAsm returns an Error REA0000: Failed to load ***.dll because it is not a valid .NET assembly

Hi,

I created a DLL in VB ,NET Framework 4.0. However, when I try to register using RegAsm, it returned an Error REA0000: Failed to load ***.dll because it is not a valid .NET assembly. Not sure what could cause it.

I'm using VS2010, and created a Class Library project, and then added a COM Class Item. And then added a public function to this class. The compilation finished w/o any issue. Any suggestion on what I should check first?

Thanks,

Yanchu