I am pretty sure that this is not due to OneCare.
The error means that there is a "double fault" condition:
Double fault
A double fault occurs when an exception occurs while trying to call the handler for a prior exception. Normally, the two exceptions can be handled serially, however there are several exceptions that cannot be handled serially and in this situation the processor signals a double fault. The two primary causes for this are hardware and kernel stack overflows. Hardware problems are usually related to CPU, RAM, or bus. Kernel stack overflows are almost always caused by faulty kernel-mode drivers.
http://support.microsoft.com/kb/137539/
Based on the fact that you are able to boot normally in Safe mode, this would lead me to suspect a driver problem.
Let's assume that it is OneCare. If you uninstall OneCare, the problem should then disappear.
-steve
