Replying to my own message, I found a reply to a similar question, and it solved my problem. I did, indeed, have to get rid of the file I had "Saved as Stationery." The message that told me how to do it was found here:
Sep 26, 2011 1:57 AM (in response to tbfa)
Sorry I didn't find this discussion before I sent out my plea. [I did a search with "stationery" and "mail" and "crash," but was told there were no such discussions. Oh, well...