As a result, information that could be used to get troubled students counseling or prevent them from buying handguns never makes it to the appropriate agency, the report by three Cabinet agencies said.
President Bush ordered the report in April after Virginia Tech student Seung-Hui Cho killed 32 students and faculty before taking his own life on the Blacksburg, Va., campus.
Cho's roommates noticed he had problems, his professors expressed concern about his violent writings, and a judge ordered him into treatment after describing the young man as a danger to himself and others.
But it's unclear whether Cho received follow-up treatment, and because the court order never made it into a federal database, he was able to legally purchase two handguns to carry out the attack.
"People don't understand what they can share and what they can't share," said Mike Leavitt, the secretary of Health and Human Services.
Meanwhile, Virginia Tech will reopen Norris Hall, the classroom building where most of the victims were killed.
The school will give media tours Thursday of the newly repaired building. Prior to this, many relatives of those injured and killed were allowed private visits to Norris Hall.
The building formally reopens Monday.
University officials have said no classes will ever meet in the building again. Engineering researchers will use sophisticated laboratory equipment there that could not be moved.
As for the federal report, Virginia Tech president Charles Steger said it disclosed "the deep complexities of the issues facing college campuses today" and reflected the dialogue on the university's campus. He said he believes the report will help advance federal and state officials' scrutiny of issues related to society's safety vs. personal freedoms.
The family of one of the victims hopes so.
"I understand privacy, I really do," said Renee Cloyd, whose daughter, Austin, was killed. "However, I think our country has come a little bit too far in saying we have all these rights."
Her husband, Virginia Tech professor Bryan Cloyd, noted that Cho's behavior had concerned one of his English professors, who removed him from class for violent writing and disruptive behavior.
"It should be pretty clear that it's a problem and that we should be able to look into that," he said. "If our privacy laws prevent that, then they need to be rewritten."
The report was released Wednesday, just after the House passed what could become the in over a decade. The bill would improve state reporting to a federal database used to block gun purchases by prohibited buyers.
Shortly after the shootings, Bush dispatched Cabinet officials across the country, ordering them to meet with school officials, mental health experts and local leaders to figure out what went wrong and how to fix it.
The report by the departments of Health and Human Services, Justice, and Education found that teachers and school administrators feared liability for sharing information and didn't understand whether they could be held responsible for not sharing information.
On top of federal privacy laws governing health and student information, states have privacy laws of their own and police have rules limiting disclosure of criminal information.
"They can in fact share information when a person's safety or the community's safety is, in fact, potentially in danger," Leavitt said.
The same problem has hampered a Virginia panel appointed by Gov. Timothy M. Kaine to review the April 16 killings as it has sought access to Cho's mental health and educational records. The panel has no subpoena authority. Its chairman has promised to go to court to pry loose the information if necessary.
"I wouldn't be surprised ... if part of the report and recommendation is, `Look, we've found it to be the case in our own work that certain kinds of information can't be shared (and) if we couldn't get it, clearly public safety officials couldn't get some of this mental health information and that may have been part of the problem,"' Kaine said Wednesday.
The federal report also recommended that schools develop systems that allow them to quickly notify students when emergencies occur.
Virginia Tech officials waited more than two hours to alert the school's nearly 26,000 students that two of their peers had been shot dead in a dormitory. By then, Cho was in another campus building, murdering 30 more people.
The school is considering programs to alert students of security issues through cell phone text messages.