SCSI Hard drive "MEDIUM ERROR"

[Ryan J. Cavicchioni]

What would this mean? I get it during heavy FTP transfers on a drive 
that is 75% full.

(da1:ahc0:0:8:0): MEDIUM ERROR info:381b12 csi:ff,ff,ff,ff asc:11,1
(da1:ahc0:0:8:0): Read retries exhausted actual retry count: 104
(da1:ahc0:0:8:0): Retrying Command (per Sense Data)
(da1:ahc0:0:8:0): READ(10). CDB: 28 0 0 38 1a a0 0 0 80 0
(da1:ahc0:0:8:0): CAM Status: SCSI Status Error
(da1:ahc0:0:8:0): SCSI Status: Check Condition

- Ryan