Word 2007 won't allow editing of Word 2003 form letter

[WMShannoX]

I have an Access 2003 database that has a number of form letters created in Word 2003. The data source for the form letters is an rtf.file generated by Access. Everything worked fine until the users switched to Word 2007. Word 2007 will not let them save an edited Word 2003 form letter. Is there some switch you can turn on in Word 2007 to allow for the editing and saving of a Word 2003 document?

Thanks for any help in advance.