The Rockies, who had labeled the problem as an "external, malicious attack", said they sold more than 50,000 tickets in the second round of ticket sales in about 2 1/2 hours.

"The online system, after a slow start, certainly worked very, very well for us," club spokesman Jay Alves said.

He said the team was sorry that not all fans who wanted to go to the game were able to buy tickets but he said the team's decision to sell tickets online was the fairest way to do it.

Bob Bowman, CEO of MLB.com, Major League Baseball's Internet wing, said Tuesday that the system was overloaded Monday by powerful computers that were programmed to constantly generate five-digit codes that are meant to prove that an actual human is trying to buy tickets. Bowman said those computers were blocked from buying tickets on Monday but their attempts to connect weren't discarded, allowing them to clog the system and ultimately knock it down.

Bowman said ticket brokers could have been responsible but he wasn't sure whether trying to trick the computer system was a crime.

"There are people who don't want to play by the rules. Those are the people who create programs to bombard these sites," Bowman said.

Irvine, Calif.-based Paciolan Inc., which operates the computer servers, didn't return phone calls and e-mails seeking an explanation about what happened.

Alves said he was unaware of any criminal investigation into what happened Monday. The FBI in Denver didn't return a call asking whether the office was investigating.

Dave Marcus of McAfee Avert Labs, the research arm of antivirus software maker McAfee Inc., said it sounded like Paciolan didn't configure its software correctly to kick off users that were trying to trick the system.

"I wouldn't call that malicious. It's just someone trying to buy more tickets than they're allowed to in an automated way," he said.

But Alves said it was malicious because it was an attempt to disrupt the Rockies' ticket distribution method. MLB.com spokesman Matt Gould agreed because he said their attempts locked fans out of buying tickets Monday.

"There were people who schemed to cause a disruption in what is a landmark moment in Rockies franchise history," he said. "That's malicious any way you define it."

Demand for tickets was high with the Rockies playing in their first World Series against the Boston Red Sox, a team with a large fan base. But many fans who hadn't been able to get through complained that only selling the available tickets online was unfair because they had to compete with people — brokers included — from around the nation and world.

However, Alves said that over 80 percent of the 12,000-plus transactions completed Tuesday were made by people with Colorado zip codes.

But with only a few thousand people able to snap up tickets, there were plenty more who weren't able to get any. Some of those fans came to Coors Field after giving up on trying to get through on their computers, hoping the Rockies would open up ticket sales at the box office.

Others, like Darlene Lugo, didn't have an Internet connection at home.

"They should have handled it differently. They should have to come in line and wait like everyone else to buy," Lugo said.

Across the street from Coors Field, Eduardo Casias had two laptop computers laid out on the back of his car, trying to buy tickets using the stadium's wireless Internet connection. His friend, Josh Bentley, waited outside the ticket window just in case.

Bentley said the online sale was unfair to local fans because it gave out-of-town buyers an equal chance at the tickets, especially if they had a fast Internet connection. The Rockies originally planned to sell tickets at Coors Field and the team's Dugout Stores in the Denver area as well as online.

"They wanted to broaden it and get the whole world involved, and there's probably people in Tokyo who are the only ones getting tickets," Bentley said.

Jerry McMorris, a co-founder of the Rockies who sold his remaining interest in the team in 2005, stopped by the stadium ticket window to pick up tickets for three games for himself and his family. He left with a stack of tickets in his pocket.

Meanwhile, Ryan Krug, 29, of Boulder left empty handed after bringing a printout of the tickets he had come close to buying on the Web site. He said the slow moving site timed out after he entered his credit card information but he said team officials told him he couldn't get tickets because he never got a confirmation number.