I get the message "One or more objects cannot be saved to the specified format" when using Architecture 2011 and 2012.  My other other machines running the same software have no problem.  Have purged and audited but it still does it.  Any suggestions will be appreciated.

Try to save it in dxf format. Then open that new dxf file and save it as dwg with some different name. Sometimes it solves the problem. Let me know it worked or not.