How errors lower your credit score

When you check your credit, you never know just what you'll find.
Probably the most frustrating thing you'll come across when you start fixing your credit is to find mistaken entries in your report. Somebody's credit boo-boo's wind up on your credit history.
It's bad enough if you yourself have racked up bad credit. It's quite another slap in the face if you're saddled with someone else's bad credit derogatory marks!
So just why DO errors show up on your credit report?
According to MyFICO.com, errors in a person's credit report might mean that their file is incomplete, contains information about another person, or any number of reasons.
Read some of the other reasons here:
http://www.findhow2.com/credit-report-errors-affect-fico-score.html