Outlook 5 Problems

Hey guys,
My mom's iMac rev. c uses outlook 5 for email. both she and my brother have an account. We use earthlink, and recently, it has been saying that outgoing messages could not be sent because "relaying messages to [user@isp.net] is prohibited by administrator." This happens in all user accounts in outlook.

I called earthlink, and they said to change the SMTP and POP servers, which I did. That did't work. I called again and got some guy who told me that "Mac keeps everything in the application itself, so you may have to delete the program and lose your messages"(uh, ok, not true u windows loving 'tard)

So, to get to my question, is there any way to export messages from outlook? My mom is obsessed with keeping all her messages. I know there is a file in the Microsoft User Data about outlook accounts, but I don't want to mess with those... What are my options, besides starting over, and his other nice little piece of advice "to call microsoft" Thanks!