In order to use the mobile player, your PPC needs to connect to the Internet.

BlueTooth might allow you to connect to a PC (via ActiveSync) and use it as a remote player but then you could just look at it on your PC if you need a PC anyway.

BlueTooth might allow you to connect to a mobile phone that had Internet access but you'd need some fast phone bandwidth (Edge, EVDO, etc) in order for it to work.

If you can get the M5 to browse the Internet with Pocket Internet Explorer, then you can try from there to get the mobile SlingPlayer working.