The network, which sells a fantasy baseball product on its Web site for about $30 and gives a version away for free, expects to have repaired a computer malfunction affecting the processing of transactions by tomorrow, said spokesman Paul Melvin.

"We're fantasy players ourselves, and we recognize that it is not acceptable for our players to have anything short of a great experience," Melvin said in a statement.

Melvin declined to disclose how many fantasy players have signed up with ESPN or how much money will be refunded. The majority of players signed up for free, he said.

In fantasy baseball, contestants build teams of big-league players and earn points based on statistics such as wins and home runs. More than 15 million people play fantasy sports; about half in fantasy baseball, according to the Fantasy Sports Trade Association.

Customers of Walt Disney Co.'s ESPN have been unable to add players or make trades since the Major League Baseball season began April 1. Scoring has also been affected. The network's Web site competes with Yahoo! Inc. and CBS Corp.'s CBS Sportsline.com for fantasy sports customers.

ESPN posted a letter to its customers April 6 that acknowledged the problem, and posted a second note two days later promising to have it resolved by tomorrow.

Meantime, customers are losing their patience, said Tom Hyde, 31, who is using ESPN's pay service to play against his fraternity brothers from his days at Virginia Tech.

"It's pretty critical to the rest of the season to adjust your roster," said Hyde, who works in the acquisitions department at Miller & Smith Homes Inc. in McLean, Virginia. "I am in three leagues, and this is the only one with problems."

ESPN promoted its free fantasy baseball product with a television commercial parodying a rock music video. ESPN analyst John Kruk sings "It's Free and It Rocks" while analyst Peter Gammons and Cincinnati Reds pitcher Bronson Arroyo play the guitar in a fake concert.

ESPN started the free version this year.

Hyde and the 11 other players in his league each will receive a refund for the 2007 season. He said he would have added Chicago Cubs pitcher Ted Lilly and Kansas City Royals pitcher Gil Meche to his team if it weren't for the glitch.

He said he is in two other leagues on Yahoo, which charges $125 per group each season. He and his fraternity brothers might switch next season, Hyde said.