If you wanted to run Jabber 1.4 server on Ubuntu Dapper (6.06 LTS) you seem to be out of luck. The unsupported version (from Universe) works great untill the last client disconnects. Then it dies silently - no log entry, no error in /var/log/messages, nothing.
It turns out that the version in Dapper Universe was compiled with gcc 4.x and this simply does not work. You have to compile it with gcc 3.x. Or - download and manually install a version from Debian repositories. Look for jabber_220.127.116.11_i386.deb.
On a sidenote: Why would anyone want to install version 1.x when there is a newer 2.x line? Bacause the 1.x uses simple XML config files where 2.x uses MySQL to save account details. For an internal deployment 1.x line seems just OK and it can run on much weaker harware, too.