ok, I had this exact same problem along with my puter rebooting whenever I started up SRO.
Turns out I had a trojan backdoor.haxdoor
Neither norton anti virus, spybot or adaware identified this, but after downloading ewido anti-spyware, I found it and was able to remove it.
Since then I have had no problems at all, can always get to the login screen without any errors. And I dont need tp reboot after SRO shut downs anymore.
No more reboots
Brett