It was good of you to quote the error signature, but it would
have been helpful if you had also quoted the actual error message
that led to this error signature. Based on your vague
description of what the problem actually is and exactly what you
are doing when the problem occurs, you might read about the issue
described in
http://support.microsoft.com/?kbid=970214 "Description of the Word 2007 hotfix package (Msptls.msp): April
30, 2009" and see if it applies to your situation.