Disk error

I ran Disk Utility on all my hard drives to check for errors. It came up with helpful little tidbits like this:

Verifying volume “Black Betty”
Checking HFS Plus volume.
Checking Extents Overflow file.
Checking Catalog file.
Checking Catalog hierarchy.
Checking Extended Attributes file.
Incorrect number of Access Control Lists
Checking volume bitmap.
Checking volume information.
The volume Black Betty needs to be repaired.

Error: The underlying task reported failure on exit

Yeah. Real helpful, Apple. Even more aggravating is trying to Google that last cryptic phrase and getting nothing but posts like this, where the guy who posted the problem somehow "fixed" it, but didn't bother to tell all the other people on the forum how.