Problems with offer

[Jeffrey K.]

I live in Wisconsin. I am not licensed. My agent was not doing a good job so I dumped him. My mom is a tax lawyer and a woman at her office helped me with an offer that I submitted earlier today. I got a call a few hours after I faxed the offer from the listing agent. She said that she had never gotten an offer from an agent that was not represented by an agent or a lawyer and is not sure she can accept this offer as valid. Do I need to have an agent to submit an offer on a property listed on the MLS? How do you guys submit offers? This might be really noobie questions, but this is my first time going it alone. Thanks in advance for all who respond.