I’'m using jive messenger 2.3 beta, and was using 2.3 alpha before that, with the same problem…
Using gaim 1.5.0, what is happening is that during logon, the status message on the gaim client is going back and forth between “authenticating” and “reinitializing stream”, until the status bar reaches the end, and one is logged on. For all I know this is normal behavior. However, a fair amount of the time the process hangs with a status message of “reinitializing stream”. I have also heard this same complaint from one of my users, and suspect it is happening to others. I would blame it on my unreliable cable modem connection, except that my aim accounts are having no trouble logging in, and they seem to be especially sensitive to network outages.
I would send copies of the jive logs, but I am having trouble reproducing the problem at the moment, to be able to nail down what log messages correspond to the problem.
However, I am willing to work closely with you to debug this situation.