By Mike Dunn and Tony Romeo

PHILADELPHIA (CBS) —  The Nutter administration has extended the City of Philadelphia’s tax filing deadline by one day, until midnight tonight, because of some web site issues on Sunday caused by human error.

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Meanwhile, taxpayers all across Pennsyvlania are also getting the extra day to file their state personal income tax returns.

The Philadelphia Revenue Department’s web site offers downloadable tax forms for certain city taxes, but the site was taken down Sunday — one day before the deadline — for routine maintenance.

If that wasn’t bad enough, human error in the city’s IT department caused the site to stay down until Monday morning.

“A series of errors occurred during the day (Sunday) and they couldn’t get the site back up,” explains Nutter spokesman Mark McDonald, who said he couldn’t elaborate on the nature of the errors.

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After the site was finally restored yesterday, officials decided to extend the filing deadline until midnight tonight for the city’s business income and receipts tax (BIRT), the net profits tax (NPT), and the school income tax.

The spokesman said that going forward, officials will “look very seriously” at whether to defer routine maintenance one day before a filing deadline.

“It was not a stellar day for maintaining that system, the day before taxes are due,” McDonald says, “and I think the administration very clearly regrets the poor performance.  And that’s why there’s a deadline extension.”

In an unrelated incident, Pennsylvania state government web sites -– including the Revenue Department’s web site -– were offline for several hours yesterday afternoon.  For that reason, the state personal income tax filing deadline has been extended by one day.  There will be no interest or penalties on returns filed by midnight tonight.

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