That means that SMART, the hard drive diagnostics, has detected that the drive is close to hardware failure. SMART also often times misdiagnoses, your best bet is to backup your data and run the drive manufacturers diagnostic utility to see what's up.
# cd /home/fuzzymuzzle.com
Intel Pentium M Dothan 750 1.8GHz 533MHz 2MB
iBase MB896F w/ Intel 915GM
[■■■■■■■■■■■■■■■■■■■■] 50% Done
(Writing Front/Back End, Designing Electronics, and Completing Install)