I, too, get this error with both the latest (21 Jan) tarballs, and a kernel
   supped as of 1 hour ago. (25 Jan). Mine will boot up and recognize my SCSI
   devices, then after probing the last disk (a cdrom) will commence to
   spew 
   probe(esp:0:6:1) timed out
   probe(esp:0:6:1) timed out
   probe(esp:0:6:1) timed out

This indicates a bug in your CD-ROM drive's firmware.  If you send me
the previous probe output, something like:

ahb0 targ 5 lun 0: <TOSHIBA, CD-ROM XM-3401TA, 3312> SCSI2 5/cdrom removable
cd0 at scsibus1: cd present, 226730 x 2048 byte records

then I'll add it to the `rogue' table.