ubuntu - BUG: soft lockup detected on CPU#0!

My Ubuntu (Ubuntu 7.04, AMD 1800XP, 2.6.20-15-generic #2 SMP Sun Apr 15 07:36:31 UTC 2007 i686 GNU/Linux) box would get halfway through booting and just sit there, doing nothing. ctrl+alt+del didn't do anything, and I couldn't get a console. To get more information, I rebooted and edited grub cmd line, taking off the 'quiet splash' options. It would get most of the way through fscking the first partition and then report: BUG: soft lockup detected on CPU#0! Not sure what causes this exactly, but I did a quick search and on some of the forums, a lot of people mentioned wireless network card as a possible source. The machine has got a wireless network card (it is a RaLink RT2561/RT61 802.11g PCI chipset), but not sure if this has anything to do with it. After a couple of futile soft reboots, I pulled the power and checked that the wireless card was properly seated, which it was, and booted the machine. It worked fine. I should try and find more out about what the error means though.