Can't run BuildOS on Vista - TypeLoadException

[SimpTheChimp]

I'm trying to run the BuildOS on my Vista partition so that I can cook my own ROM. I have everything installed; however, when I try to run BuildOS I get the following error immediately:

Description:
Stopped working

Problem signature:
Problem Event Name: CLR20r3
Problem Signature 01: ppc-buildos.exe
Problem Signature 02: 9.5.0.0
Problem Signature 03: 48db103a
Problem Signature 04: Microsoft.VisualBasic
Problem Signature 05: 8.0.0.0
Problem Signature 06: 4757a7c2
Problem Signature 07: 6c
Problem Signature 08: 46
Problem Signature 09: System.TypeLoadException
OS Version: 6.0.6001.2.1.0.256.1
Locale ID: 1033

As far as I can tell I have all the .NET Framework versions installed correctly - even 3.5! I also have everything updated properly. And I am running this as the Administrator.

So anyone got any ideas as to why this won work?

Chimp (Tom)