I use the extremely useful SyncToy to mirror my data between various machines at home. However, it did not work on Vista x64. I found this very handy blog post which tells you how to fix the problem. I didn't feel like installing Windows Network Monitor 3.1, so I decompiled it using dark and extracted the needed file out of the msi. I'm attaching it here for anybody that's interested.

Here's an example of the error that you'll see if you have the problem:

Problem signature:
  Problem Event Name: CLR20r3
  Problem Signature 01: synctoy.exe
  Problem Signature 02: 1.4.0.0
  Problem Signature 03: 453f990b
  Problem Signature 04: SqmManagedWrapper
  Problem Signature 05: 1.4.0.0
  Problem Signature 06: 453f9909
  Problem Signature 07: 8
  Problem Signature 08: 38
  Problem Signature 09: System.BadImageFormatException
  OS Version: 6.0.6000.2.0.0.256.1
  Locale ID: 1033

Here's how to fix the problem: 

• Rename custsat.dll in the installation directory for SyncToy (C:\Users\[YourLoginName]\AppData\Local\SyncToy\ by default) to custsat.dll.original so that you can restore the file if you want.
• Copy the custsat.dll file attached to this blog post to C:\Users\[YourLoginName]\AppData\Local\SyncToy\ (or wherever you installed SyncToy).

That's it. You should be good to go now. I need to log a bug on this for the SyncToy team if one hasn't been logged already.