Another school-related campaign blunder landed Fernando Ferrer in the principal’s office for the second day in a row yesterday.

On Tuesday, Mr. Ferrer admitted that his personal campaign Web log – on which he said he spent most of his school years in public schools – was incorrect. A New York City Catholic community leader, Bill Donohue, lambasted the Democratic mayoral nominee for obfuscating his parochial education and said he had “turned his back on Catholics.”

Yesterday, as Mr. Ferrer attempted to fend off the blog-related attacks, he violated a long-standing regulation that forbids political candidates from setting foot inside New York City public school buildings within 60 days of an election unless they are public officials conducting official business.

With only 41 days remaining until New Yorkers head to the polls for the general election, Mr. Ferrer – who currently has no job, official or otherwise – made a late-morning visit to Flushing High School in Queens to address a class of 12th-graders.

The chancellor’s regulation, which has been in place in its current form since 2001, according to the Department of Education, makes it clear that school buildings “are not public forums for the purposes of community or political expression.” Other candidates, including Mayor Bloomberg and Mr. Ferrer’s opponents in the Democratic primary race, filmed campaign advertisements in non-public schools to avoid breaking the regulation.

Mr. Ferrer played down the importance of his school appearance, which his campaign included on his public schedule.

“I didn’t campaign,” he said, standing on the sidewalk outside the school upon exiting. “I made it a point to talk to these kids about civic participation and my own experience with it at a young age. I talked to them about some of the things that inspired me.”

Mr. Ferrer’s spokeswoman, Jen Bluestein, saying the campaign was not aware of the specifics of the chancellor’s regulation, defended Mr. Ferrer’s appearance.

“If Mike Bloomberg thinks those kinds of conversations are not the kinds of conversations we should have with our kids as we try to make the city better, that’s just another difference between him and Freddy Ferrer,” she said.

According to the Department of Education, a teacher at the school a couple of weeks ago invited Mr. Ferrer to address a class. The principal agreed to the visit. In accordance with the chancellor’s regulation, the education department reported the visit to the Special Commissioner of Investigation for the city schools, Richard Condon. As of yesterday evening, Mr. Condon said he did not intend to investigate the event.

Mr. Ferrer’s school troubles were not over when he left Flushing yesterday.

Mr. Donohue, the president of the Catholic League, sent an e-mail to reporters, blasting Mr. Ferrer for trying to run from his Catholic-school upbringing.

“Freddy (as he affectionately calls himself) Ferrer is all over the New York news for advertising himself on his Web site as a product of public schools when, in fact, he went to Catholic schools from K-12,” Mr. Donohue wrote. “When asked about this yesterday, all he could say was that it was ‘nonsense’ to say he lied about his schooling. What he still could not do was to say that he went to Catholic schools, and his revised Web site makes no reference to his parochial education either.”

Mr. Ferrer’s blog originally said, “I was born in the South Bronx and educated in public schools for most of my education.” The corrected entry read: “I was born in the South Bronx,” leaving out the candidate’s schooling altogether.

Mr. Ferrer’s elementary through secondary education doesn’t appear in the official biography on his campaign Web site either. Although it says he was born in the South Bronx, it doesn’t mention any education until college.

Mr. Donohue said Mr. Ferrer’s mistake was not an isolated incident.

“This is not the first time that Freddy-the-Faker-Ferrer has turned his back on Catholics,” he wrote. He then listed a number of times in the last decade when Mr. Ferrer has failed to stand up for Catholics.

“In 1996-97, when Mayor Rudy Giuliani floated the idea that one way to stem overcrowding in the public schools was to send students to Catholic schools, the Faker went mad,” Mr. Donohue wrote. “No doubt he would be just as mad to learn that his challenger, incumbent Mayor Michael Bloomberg, is a contributor to the Catholic Schools Foundation.”

Mr. Donohue wrote that Mr. Ferrer offended Catholics in 2001 when he didn’t march in the St. Patrick’s Day Parade.

Mr. Donohue also bashed the Democratic candidate for suing to keep Mayor Giuliani from withdrawing city money from the 1999 “Sensation” exhibit, which featured a work called “The Holy Virgin Mary” that was festooned with elephant dung. At the time, Mr. Bloomberg, who attended the exhibit’s opening, was quoted as saying, “I don’t understand why there is a fuss about this. To me, there is nothing sacrilegious about the art.”

Mr. Donohue’s message concludes: “Makes you wonder: Who’s Catholic? Freddy-the-Faker-Ferrer or Mike Bloomberg?”

Ms. Bluestein, of the Ferrer campaign, said, “I think that Mr. Donohue has a track record of very ugly attacks on people. Freddy is very proud of his Catholic education, and his 20 years in public service have been informed by many things, including his faith.”

She declined to discuss Mr. Donohue’s specific charges, saying, “He’s certainly not a person who has informed Freddy’s thinking about how to serve his community, and his vituperative comments seem out of keeping about how we can form a better city for all of us.”