I cannot upload file with either Uploader.

I am trying to upload a dj set in MP3 format. I tried the uploader, it took 2hours and then I got an error message saying "are you sure this the right type of file". I had another 2 attempts and still either an error message or it just stops and restarts.

I then tried the old school uploader. Still no success, no indication that anything is happening.
I am running Mozilla firefox 3.5.1 on vista and have shockwave flash 10.0.22.87