Not a valid assembly (Add Reference failure)

When trying to add a reference to a VB DLL, you may receive the following error popup: A reference to

'assemblyname.exe' could not be added. This is not a valid assembly or COM

component. Please make sure that the file is accessible, and that it is a

valid assembly or COM component.

WorkAround:-
There were some on the net, but I registered the DLL using regsvr and added it from the COM components tab and it worked fine.