The organization, New York Senate 2000, agreed to a federal finding that it failed to report $721,895 spent on the fundraiser to boost the former first lady's campaign for Senate, according to paperwork provided by Peter F. Paul, who helped finance the star-studded gala that drew Cher, Diana Ross, Brad Pitt and Jennifer Aniston.
Paul filed the initial complaint that led to the investigation, and on Thursday provided a copy of a signed agreement between New York Senate 2000 and the Federal Election Commission.
An FEC spokeswoman said no documents had been filed publicly and declined comment.
Marc Elias, a lawyer for the Clinton campaign group, did not immediately return calls for comment. The deal was first reported in Thursday's editions of the New York Sun.
"It's a kind of vindication, but this is only one battle," said Paul, a three-time felon who is suing both Sen. Clinton and her husband Bill Clinton, claiming he was led to believe the former president would later work for him in a private business venture.
As part of the agreement, New York Senate 2000 maintains it "implemented and enforced reasonable processes to collect and report information regarding event expenses," according to the document.
The Hollywood fundraiser was the subject of a criminal trial last year of Clinton's former national finance director David Rosen. Rosen was acquitted in May 2004 of lying to the FEC about the event.
Paul has claimed the event cost more than $1.9 million, even though campaign reports at the time put the price tag at about $500,000. As part of the agreement, the actual cost is now put at $1.2 million, with almost $400,000 unreported for the cost of producing the concert, and nearly $100,000 unreported for travel and lodging costs.