envelopes properties in word print address in the return address spot

[pkp325]

I am using office 97. When I highlight the address and tell it to print an envelope it will sometimes print it in the return address location. I have to mess with the margins to get it in the right place. I have my return address omited most of the time. It doesn't put it in the wrong location everytime. I go to the same document to pull addresses and sometimes it messes up and sometimes it doesn't. I can't figure out why it does this.
Thanks for your help!