ok, I haven't got eloader in front of me, but.....
I think there's a setup page
in the drop down menus to choose which midi ports you're P2K is connected to (if you've
got a MS2x2, best to check you've got the correct ones?) E Loader has to be able to see
which machine it is connected to (P2K, MP7, Xlead, etc) by 2 way communication.
Also, with it being a 2x2, make sure you've got the 'thru/USB' switch in the correct
position (USB) so the computer can communicate both ways with the P2K (PS, you have got a
midi in AND out connected to the P2K, right?)
You have to choose the OS you
want to download to the P2K before the 'download' box will appear properly, I think?
My biggest concern for you is that ELoader was never written for Vista, and I
don't think they updated it. Have you used it before trouble free? I've always used it
on XP, so I can't speak from experience but it may not actually run properly.
Hope something there helps, I'll check in further detail when I get home tonight to see
if I can come up with anything else