After last update i start to get this kind of error. I can't identify then it's log off and then it's a disconnect. But i know for sure, then it's disconnect - i have got an error message (on log in screen), but sometimes it's even do not give me any error message - just kick on log in screen. I also check game folder for error reports, but did not find anything there.
Before last update everything was o.k. (on hellowen).
2011/11/07 16:29:44:547 INFO I$a.b: Logging to 'd:\games\steam\steamapps\common\spiral knights\.\projectx.log'.
2011/11/07 16:29:48:999 INFO I$a.b: Steam initialized.
WARNING: Found unknown Windows version: Windows 7
Attempting to use default windows plug-in.
Loading: net.java.games.input.DirectAndRawInputEnvironmentPlugin
2011/11/07 16:29:53:356 INFO I$a.b: Connecting [host=game.spiralknights.com/184.73.192.155, port=47624]
2011/11/07 16:29:55:405 INFO I$a.b: Datagram connection established [port=47624]
2011/11/07 16:30:01:190 INFO I$a.b: Moving at request of server [zoneId=16777217, sceneId=1]
2011/11/07 16:30:01:549 WARNING I$a.b: Failed to find property. [name=portal, object=[actor=null, location=[]]]
2011/11/07 16:30:01:549 WARNING I$a.b: Failed to find property. [name=scene_id, object=[actor=null, location=[]]]
2011/11/07 16:30:01:713 WARNING I$a.b: Failed to find property. [name=conditions, object=[tag=, all=false, target=[]]]
2011/11/07 16:30:01:903 INFO I$a.b: Issuing zoned moveTo(1:1, 1, 74).
2011/11/07 16:30:02:213 INFO I$a.b: Connecting [host=/50.17.78.53, port=47624]
2011/11/07 16:30:03:726 INFO I$a.b: Datagram connection established [port=47624]
2011/11/07 16:30:04:496 INFO I$a.b: Issuing zoned moveTo(1:1, 1, 74).
2011/11/07 16:30:05:875 INFO I$a.b: Updating outgoing message throttle [msgsPerSec=15]
2011/11/07 16:30:31:450 WARNING I$a.b: Really long invoker unit [unit=News Reader (class com.threerings.projectx.client.aI), time=7940ms].
Ping 184.73.192.155 give me 100% lost
Was that log right after you got kicked off? It just shows you logged in and the news page popped up.
check the projectx.log and look for any network related exception errors.