I'm getting this every 2-3 days of uptime. It happens randomly. It could be working online, it could be doing nothing. usually it's doing something idle, such as the screensaver, because I'm away from it more often than not throughout the day.
The error report always indicates a failed memory allocation call. The offending process is always different though, seemingly random... been everything from the kernel, to x-chat, to geektool.
I've taken it to apple on three separate occasions regarding this, and they haven't been any help. They say everything checks out, not overheating, etc... I call bollocks, because I know the core temp gets above 103C under load, according to both iStat in Leopard and CoreTemp in Windows (bootcamp).