Ok, the problem is the patch.
1) It could be the PSOBB client I had here on my computer that wasn't working as the Ultima Server expect.
2) The patch may have some issues.
I've downloaded the Ultima PSOBB Client and everything is working fine now.
Whoever had the same problem I had, it's good to post and warn the Ultima Server Administrators, so they can work in a solution (only if the problem was really the patch).
Simple connection, though, not complicated at all, and you guys are doing a great job