I had the same error message a couple of months back - unfortunately, it was the initial stages of a dying hard drive that ultimately led to a loss of data and more frustratingly time.

The first thing to check is of course the cable. Check that it is connected correctly and, if possible, try another cable to try and rule out error. Your next step is to try and load a disk checking utility - see the above link for how to start the recovery console and use chkdsk.

Failing that, it could be a terminal problem and I advise you get it installed as a slave drive on another machine and try recovering data from there. I was fortunate as I had mine partitioned so I only lost my Windows drive.

Whenever you have a disk problem like this, ensure you backup any data if at all possible - it is times like this you'll really appreciate a proper backup routine. Use a disk utility to scan the whole drive thoroughly, and even if it comes back saying the drive is fine, be cautious. My drive was reported to be fine so I reformatted it and started again - less than a month later it errored again twice and is now at the bottom of a landfill site.

I really hope it is just a cable error or a rogue sector and nothing too serious.

John