Windows 7: Adding Extender freezes

I'm trying to add my 360 for an extender and I keep getting the same error



I'm running Windows 7 64bit, I've downloaded all of the windows updates, repaired and reinstalled the .net frameworks, tried in safe mode, clean boot, etc.

Right after i type in the 8 diget key it freezes and gives me this error.

Description:
Stopped working

Problem signature:
Problem Event Name: CLR20r3
Problem Signature 01: ehshell.exe
Problem Signature 02: 6.1.7600.16385
Problem Signature 03: 4a5bd053
Problem Signature 04: ehshell
Problem Signature 05: 6.1.0.0
Problem Signature 06: 4a5bd9da
Problem Signature 07: 2970
Problem Signature 08: 10
Problem Signature 09: System.NullReferenceException
OS Version: 6.1.7600.2.0.0.256.1
Locale ID: 1033

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Any help would be great!