Microsoft has now released a KB article addressing this issue. The KB describes some conditions in which this issue would also apply to Office 2007 implementations if other products are also installed that would require this security update.
Can you confirm that this issue occured for you as well after December 9th? If you check the update history has there been any security updates installed since December 9th?
If so it might be worthwhile searching for the MSForms.exd files and deleting them in your Office 2007 installation as well to see if this resolves the issue.
MS Office KB: http://support.microsoft.com/kb/3025036