A very quick speed-read of what you provided suggests it was a software issue.
There isn't anything obvious to point to a hardware issue.
Tar your corefiles together. Include all the messages* files that are on that system.
Use your service contract and open a support request.
Get the SR forwarded to the Kernel Support Group.
Have that Kernel group guide you to forward the corefiles to them.
Techupport has special software applet tools that can analyze what may have happened.