I dont seem to have that kind of problem before. but here's what i always do/remember when uploading torrents.
1.) Upload the .torrent file first before seeding.
2.) make sure to use the
http://tracker.datorrents.com:6969/announce.php as the announce url.
3.) make sure that .torrent file will accept peers from the tracker only.
4.) set your client to accept peers from the tracker only as well.
5.) Fill in everything in the Upload field: Torrent file, Torrent name, Description, Type.
with those things, i never fail or get an error in uploading.
note: make sure you use the browse on the Torrent file field, not the NFO File Field