Customers at a New York City KFC hoping to redeem coupons for a free meal were peeved when the fast-food eatery's supply ran low, but Internet rumors of a riot were false, a KFC spokeswoman said Wednesday.

"Some customers were upset because they couldn't get their chicken, but there was no riot," said Laurie Schalow.

The coupons were available on Oprah.com for 24 hours beginning Tuesday after Oprah announced the meal promotion on her show. Each downloadable coupon can be redeemed for two pieces of grilled chicken, two individual sides and a biscuit.

On Thursday, KFC president Roger Eaton issued an apology for the coupon fiasco, but said the chicken giant will no longer accept the coupons.

"We would like to apologize to our customers who have been inconvenienced by the overwhelming response to our free Kentucky Grilled Chicken offer," Eaton said in a statement. "The lines of customers wanting to redeem their coupon have been out the door and around the block, so we're unable to redeem customer coupons at this time. Instead, we will be issuing rainchecks to customers which can be used at a later date. We're asking our customers to kindly visit their local KFC to find out more about rainchecks."

KFC, owned by Louisville, Ky.-based Yum Brands Inc., introduced its new Kentucky Grilled Chicken about three weeks ago. The new menu item is being touted as lower in fat, calories and sodium than the traditional deep-fried chicken for which KFC is known the world over. It even has its own secret recipe, kept under lock and key near the original 11 herbs and spices recipe for fried chicken created by KFC founder Colonel Harland Sanders.

Schalow said the grilled chicken has been a huge success, and the combination of a bad economy and Oprah's popularity created a "perfect storm."

"We prepared for it," Schalow said, noting that a KFC restaurant can only serve so many people during the lunch and dinner hours. "We didn't prepare for this extreme."

But Schalow said customers have until May 19 to redeem their coupons, Mother's Day excluded, and she encouraged the public to return later.

A spokewoman for Oprah's Harpo Productions in Chicago said they are not aware of any problems with the coupons.

Schalow said KFC restaurants across the United States were bustling on Wednesday because of the coupon offer.

"A lot of restaurants experienced very, very heavy traffic with people trying to redeem the coupons." she said, though KFC headquarters did not hear of any other problems with customers other than the those at the New York City franchise. "All stores are very busy today, very long lines, that's what we're hearing."

Schalow said some KFC stores may have run out of some products, such as mashed potatoes and gravy or cole slaw, "but they are substituting as best they can."

The Associated Press contributed to this report.