Error adding reference to the project

Hi,
I'm having trouble adding a HASP dll to a VS 2003 C++ project using the IDE. I've done this loads of times with other dlls in C# projects with no trouble. The error is:

Add Reference: Error adding reference to the project.

I've Googled the problem and tried regsvr32 but i get the message:

haspms32.dll was loaded, but the DllRegisterServer entry point was not found. This file cannot be registered.

I've tried all the solutions on Google to no avail. Anyone here have any ideas?

Thanks