LAWRENCEVILLE — Gwinnett County was four months late on paying dues to the Atlanta Regional Commission.

Officials blamed the error on an invoice addressed to one of the 200 people who retired from the county last year.

A check for the October installment of the quarterly dues was mailed recently, and the January check was delivered Thursday, said Community Services Director Phil Hoskins.

Hoskins said the county did not have to pay late fees and determined the error when the January bill arrived.

“It’s just a mistake,” he said. “This is not a lack of dollars or anything like that. ... We don’t know what happened to the invoice.”

Dues to the commission, which formulates transportation plans to conform with air quality standards and has a role in planning, aging and other issues, are $1 per resident for each of the region’s 10 counties.

Gwinnett’s October payment was $188,700. It increased slightly for January, as the county population estimate continues to increase. That installment was $189,825, Hoskins said.