The problem is that the server process is 64 bit and the library is 32-bit and it tries to create the COM component in the same process (in-proc server). Either you recompile the server and make it 32-bit or you leave the server unchanged and make the COM component out-of-process. The easiest way to make a COM server out-of-process is to create a COM+ application - Control Panel -> Administrative Tools -> ComponentServices.