Hello, Ted
I also used to work normally with debugger until there was some change/upgrade in my Visual Studio settings. I work with VS 2012 on day-to-day basis and PB.NET, as you know works with VS 2010 shell.
I attached the process explorer output for pbshell.exe
Please, compare the dll list + versions to the one you have and tell me which dlls are missing or have disfferent versions.
This is the only course of action I have here.