>The code in question tries to run as FoxFire is an "add-in" so it attempts an install when it is launched from within a custom app (i.e. my app). But it is very old. I have not yet tried to install the .ocx manually yet as looking at their code, it seems like it is not just a "regsvr /ocxfile" situation. I guess I will have to wait for their tech support.

Then run cmd.exe as admin, and there regsvr32.