Carl; Perhaps we are speaking of two different terms.

Sometimes chips are issued with mistakes on them ... like maybe a mis-spelled word ... or an incorrect date. These are not "errors" if all the chips issued have the same mistake. An error on the other hand is one-of-a-kind ... or only a few known.

The type error is also important. Double sided errors where the same design is on both sides of the chip instead of different designs on each side of the chip are very popular. Generally speaking, they bring anywhere between $200-$400 in the A.C. market. A chip with a $5 denomination on one side and a different denomination on the other side (except for Bud Jones metal center chips that can be easily switched) are also popular errors that can be worth several hundred dollars. Missing edge insert chips are also very popular errors. Generally speaking, I've found that A.C. error chips generate more interest than Nevada errors do.

You'll have to be more specific in describing your "error" chip. Better yet, post a scan.