Infopath 2007: Adding contact selector gives CoCreateInstance failed.

I've tried to add the contact selector to my dev environment. I followed the steps here:

http://blogs.msdn.com/b/infopath/archive/2007/02/28/using-the-contact-selector-control.aspx

But at step 4 I get:

CoCreateInstance failed to create the control.
- The control may not be properly installed or registered.
- The control may have missing dependencies.
- Only controls implemented as InProc servers (.DLL or .OCX) are supported.

Solution:
I ran an "Office Diagnostics..." and it fixed the issue.

In Infopath 2007: Help > Office Diagnostics...

At least I think this is the fix. I have been tinkering with my system in attempts to fix this. If it works for you please comment here to confirm.

I think there might have been a new version of the ContactSelector.dll control installed somehow and Infopath 2007 didn't like it.