I made the IPv6 remark, because even if your provider does not have it enabled, Windows Vista and above have per default. Any other machine in your subnet can announce itself as IPv6 router, and then Windows will totally enable IPv6 on your network card. If then incoming connections are not filtered as expected, the firewall is successfully circumvented. However, you also mentioned a DMZ, so we are speaking about a hardware firewall as well?
The reason why I am even interested in that is that we have had weird firewall issue before. Some firewalls did not like that Uru disconnected from port 5000 and connected to another port later on, and blocked that subsequent connection (to the game server). In this case however, the connection drops before any game server is involved. Others seemed to consider UDP traffic they do not know on ports they do not know suspicious, or similar. It's really fishing in the dark and guessing based on experience
The log file looks fine, but it dos not tell me much as the interesting packets are cut (due to the max size limit), so the Uru protocol analyzer just says the length byte in the message is wrong. Could you increase the limit to at least 512 and try again (or remove it alltogether)?
If you want to be sure that only Uru communication is captured, you can extend the filter with "&& ip.addr == 85.214.57.193". The way the Uru protocol works, your password is not transferred in clear-text, and the authentication is immune against replay attacks (so uploading the login process is as safe as the underlying hash... okay, that's MD5 ). You can also email it to diafero AT arcor DOT de if you wish.
I just logged in to your account without problems, so the issue seems to be on your connection.
How have you been able to create that one avatar at all?