kernel[0]: disk0s2: media is not present.

I can find no reference to rdisk0s2 on the whole system. My boot disk is a pair of mirrored 80GB drives, disk1s2 aqnd disk2s2. No disk0s2 in /dev. Got these after a new user was trying to log into mail with the wrong username, a bunch of times.

Jun 25 09:51:26 flatrack kernel[0]: disk0s2: media is not present.
Jun 25 09:51:26 flatrack kernel[0]:
Jun 25 09:51:26: --- last message repeated 1 time ---
Jun 25 09:51:26 flatrack kernel[0]: HFS: err 6 reading VH blk (Untitled)
Jun 25 09:51:26 flatrack kernel[0]: jnl: disk0s2: flushing fs disk buffer returned 0x6
Jun 25 09:51:26 flatrack kernel[0]: disk0s2: media is not present.
Jun 25 09:51:26 flatrack kernel[0]:
Jun 25 09:51:26: --- last message repeated 1 time ---
Jun 25 09:51:26 flatrack kernel[0]: jnl: disk0s2: do jnlio: strategy err 0x6
Jun 25 09:51:26 flatrack kernel[0]: jnl: disk0s2: write journalheader: error writing the journal header!
Jun 25 09:51:33 flatrack kernel[0]: [0 0 0] Command completion error, flag(a0)
Jun 25 09:51:33 flatrack kernel[0]: start channel [0,0]
Jun 25 09:51:33 flatrack kernel[0]: channel [0,0] started successfully
Jun 25 09:51:33 flatrack kernel[0]: [0 1 0] Command completion error, flag(a0)
Jun 25 09:51:33 flatrack kernel[0]: start channel [0,1]
Jun 25 09:51:33 flatrack kernel[0]: channel [0,1] started successfully
Jun 25 09:51:34 flatrack Console[76238]: * -[NSConcreteFileHandle offsetInFile]: Bad file descriptor
Jun 25 09:51:41: --- last message repeated 1 time ---
---cut---
Jun 25 09:54:38 flatrack Console[76238]: * -[NSConcreteFileHandle offsetInFile]: Bad file descriptor

then...

Jun 25 09:55:11 flatrack quicklookd[76398]: EXCEPTION CPMessageException: (null)

I launched Disk Utility, and the errors went away.

***!? Any Ideas?