PyICQ-t and Authentication Error

Hello. Have happily been using Jive Messenger and Neos client (all Windows) for some time, just now got round to playing with transports. Have PyICQ-t installed and - seemingly - running, and the service shows up, allows registration, shows up the test account and a friend account, but then, after 5 seconds or less, get logged out with the following error:

icq (13:09:09):

Authentication Error!

x00
x1d

I saw one reference to this on a German forum, but am getting absolutely nowhere. Any ideas? Thanks. Oh, this is running through a local proxy server.