You may need to run the WinDU EPM Family Table Validation report. Most likely the family tables have some errors that need to be corrected either via the FTHealer tool (available through technical support--you will need to open a case).
Or it may be possible that this is occurring due to a bug as was the case for another Community member mentioned here:
http://communities.ptc.com/message/245313#245313
Related article:
https://www.ptc.com/appserver/cs/view/solution.jsp?n=CS113353
Information on running the WinDu FT Validator is found here:
http://www.ptc.com/appserver/cs/view/solution.jsp?n=CS130922
Either way, it will be necessary to open a technical support case to get the errors fixed.