I have recently had to rebuild a C# interop created for calling from VB6. I have registered it with regasm (using codebase switch) and added the tlb as a reference to the VB6 project but when I attempt to call it I get the following automation error: -2146232832 (0x80131600)
If I register the existing interop dll in exactly the same way and add to my project, it works fine. The only differences I can think of are that the project has since been upgraded from VS8 to VS9 (same .net version though), and I'm now compiling on a 64-bit machine (which I know there are issues around this). I have set the project to compile as x86 but I still get the automation error.
Any ideas??