no matter what at any hotel anywhere you will show up as "firewalled" ie ports blocked. this generally doesn't matter and you can still upload. as you found out this isn't always the case.
couple things. never use the "bit torrent port" 6881 or whatever. use something random over 30k (at home as well).
if there is a ethernet connection use it instead of wireless.
check if you can upload before hand. I find a torrent on etree with a roughly even number of seeders and leechers. jump on for a few mins to see if you are able to upload. remember at the hotel your ports are always "blocked" but it shouldn't matter most of the time. if you are able to upload on a regular torrent you should have no issues seeding one.
NEVER ask the hotel about blocked ports or let them know what you are doing. they don't like you taking all the bandwidth
so moral of the story is 99% of times uploading from the hotel goes off without a hitch even though you are "firewalled". 1% of the time you can't. better luck next time!