I can corroborate Korinther’s statement that RefMan 12.0 works with Word 2010. Just installed Word 2010 today and found to my horror that RefMan 12.0.2 causes it to hang. So I uninstalled RefMan after reading these comments and reinstalled version 12. Now CWYW works.
However, please, Thomson-Reuters, make an upgrade as soon as possible! I use RefMan daily too.