I've tried to put a song of my own on this site and I always get file not valid but I've tried all possibilities that I could think of but it just keep on saying that I have absolutely no idea what the problem is

just a thought - is it an mp3?

im not trying to take the mick, but its often the obvious things that you dont notice.

is it larger than 5Megs? I don't think that the site accepts anything over 5 megs, though I've never seen this documented anywhere.

I think it's more like 7MB, not sure off the top of my head though...

Try re-encoding the mp3 a lower bps(ex instead of 192 bps, make it 160 to get it under 5 megs) When i tried to upload mine ,I took it straight out of the windows media player format; it was almost 15 meg!!!(lol) Didn't realize it right away.