The Illinois Lottery bounced dozens of checks written to winners, many for scratch-off tickets worth $1,000.

Lottery spokesman Mike Lang says the mistake happened when a computer file wasn't sent on time to the lottery's bank. He says lottery officials didn't key in the required security verification for the checks.

The lottery wrote 311 checks on Dec. 28. Of those checks about 85 bounced. Lang says the lottery offices were short staffed because of the holidays. The affected checks totaled about $159,000.

Lang says the lottery will pay for any bank fees that occurred because of the checks. The lottery also is apologizing by sending free scratch-off tickets to those affected.