Yeah, sounds like your video card is just too old...PM requires Shader2 or better.
If you've been looking to upgrade to a newer one, you can get a Shader 3 compatable card for around $25 online. In fact, here's one that's actually Shader4 compatable for $18.99 after a mail in rebate.
http://www.newegg.com/Product/Product.aspx?Item=N82E16814127241
Of course, if you still just want a refund, email support@stardock.com and they can get you started on the refund process 
Hope these options help!
