CHICAGO (CBS) – The Chicago Park District experienced problems again Monday morning as it opened up online registration for its summer camps.

WBBM Newsradio’s Nancy Harty reports, within the first two hours of online registration for summer camps, roughly 16,000 parents logged onto the Park District website to sign up their kids for summer programs.

However, less than half were able to get receipts for camps or other programs after trying to sign up.

LISTEN: WBBM Newsradio’s Nancy Harty reports

District spokeswoman Jessica Faulkner said the difference is hard to pin down.

“They could have either decided that they didn’t want the program; the dad could have got the program, instead of the mom. We’re not able to tell that right now,” she said.

Faulkner said officials expected a lot of interest in summer programs and they got it. The high traffic slowed down the site, but it did not crash this time, as it did in February when it was used for the first time for registration for spring programs.

As of 12:30 p.m., 20,000 people had registered for summer programs, compared to 15,160 registrations during the entire day on the first day of sign-up last year.

Parents frustrated with the problems on the site Monday took to the district’s Facebook page to lodge complaints about wait times of more than an hour to complete a single registration, repeated error messages, and slow confirmation of successful registrations.

Others complained that, after signing up one child for one program, they could not get another list of programs to sign up their other children.

Faulkner said error messages don’t always mean a transaction was not completed.

“If you receive the congratulations page, then we’re pretty certain that you received your transaction. You should go to your account and be able to look to see exactly what you were able to get and see your receipt number,” she said.

Faulkner said record volume led to longer wait times than they had anticipated. Officials were working with the developer to fix that.

Many users asked why there were problems for a second time after the site was redesigned earlier this year. The registration system crashed in February when parents tried to sign up for spring programs at the parks, forcing the district to add extra servers to traffic they claimed was four times higher than the same time last year.

The district encouraged parents to have patients, or try a different Internet browser program. Officials also noted that, for some programs, parents can sign up in person at their preferred park on Saturday.