Console spam prior to reset

For the past week my server is randomly closing after my console is spammed with the following (100's of times):

Code:

2011-03-16 01:55:29 [INFO] [CONSOLE] Welcome back, Killburner
2011-03-16 01:55:29 [INFO] Unknown console command. Type "help" for help.
2011-03-16 01:55:29 [INFO] Unknown console command. Type "help" for help.
2011-03-16 01:55:29 [INFO] Unknown console command. Type "help" for help.
2011-03-16 01:55:29 [INFO] Unknown console command. Type "help" for help.
2011-03-16 01:55:29 [INFO] Unknown console command. Type "help" for help.
2011-03-16 01:55:29 [INFO] Unknown console command. Type "help" for help.
2011-03-16 01:55:29 [INFO] Unknown console command. Type "help" for help.
2011-03-16 01:55:29 [INFO] Unknown console command. Type "help" for help.
2011-03-16 01:55:29 [INFO] Unknown console command. Type "help" for help

I'm on CB#527, current Java, with a fairly standard & updated plugin list (WorldGuard, WorldEdit, BB1.7, Dynmap). After the crash I manually startup again and I'm stable for 12-24 hours. If it was more frequent, I'd experiment by removing plugins but this will forver to narrow down, assuming it's a plugin issue to begin with.

Any ideas before I start digging into this one further?