If you're completely flummoxed by a recent Baltimore property-tax bill, you're probably one of the 7,900 or so city homeowners whose accounts were upended by a state computer error.

The mix-up resulted in past-due notices -- some for thousands of dollars -- for certain residents who bought a city home during the tax year that ended June 30.

Some recipients of the Homeowners' Property Tax Credit for lower-income residents, meanwhile, received incorrect bills for the tax year that began July 1. They were just sent out a second set last week with the right figures -- some higher, some lower.

Folks with past-due bills they shouldn't have received will be mailed notices next week setting the record straight, the city says.

Owen C. Charles, supervisor of the state Department of Assessments and Taxation office in Baltimore, said the computer trouble affected the value of tax credits in both situations. (The bills themselves came from the city, since the assessors don't collect. Once the wrong information was shipped to the city, it was automatically turned into bills.)

More details in today's story.

UPDATE on Thursday: I thought both the state and the city were agreeing yesterday that the problem begin with the state, but Charles says this morning that it's too early to say whose fault it is. He's still investigating. He says he is certain the state's property database itself is accurate, and the problem was tax-credit information incorrectly applied. (Application of tax-credit information is the city's job, he says.)

"I couldn't tell you exactly what the problem is -- I just know it's not with the state's data," he says. "We're hearing from the city it's the state's fault, so we're trying to ensure if it's the state's fault, we rectify the situation."

As I was trying to get to the bottom of the wrong bills, a reader emailed to say she'd run into another assessment problem.