Just wanted to report that after upgrading to Mac OS X 10.5.3,
Vine Server works better than ever. I actually did the update
remotely via Vine Server with no problems, and System Server
allowed me to log in again after the reboot (after restoring the
wireless SSH pipe).
My system is a C2D iMac with Vine Server beta 3.1, connected
from Windows XP with TightVNC client 1.3.9. I used the 10.5.3
combo update from Apple.