Debugging a C++ COM object (ActiveX DLL) from a C# windows service

I am attempting to debug a C++ COM object (ActiveX DLL) from a C# windows service.   When I set the Debug Command in the C++ project to; net start " PhysicalAccessService", I get the following error:"Parameter "basePath" cannot have zero length. I have tried attaching the debugger to the service after starting it from the Computer Management console, but it steps over the unmanaged code even though I have the unmanaged debugger option checked in all the managed modules.