I had some who had their envelope settings changed from auto and they were getting annoyed that they had to change them back to auto every time they wanted to print an envelope.  I found this web page
http://www.gmayor.com/changing_envelope_layout.htm with good directions on how to fix this for Word 2003 and 2007.  The setting for the envelope are stored in the normal.dot file and the web site includes directions and pictures of Word on how to fix the issue.