Rep. Norm Dicks (search), D-Wash., said Tuesday he has paid $571 to a lobbying firm that had paid for a trip he took to a military conference in Florida.

Dicks said he made a mistake by allowing the Spectrum Group (search), a defense lobbying firm, to pay for his lodging and meals during a two-night stay in Fort Lauderdale in February.

He is a senior member of the House Appropriations Committee, which plays an influential role in defense spending. He called the violation unintentional, adding that he corrected the error after it was brought to his attention by a reporter for Roll Call, a newspaper that covers Capitol Hill. The paper published a story Monday on the trip.

"I made a mistake and I corrected it as soon as I figured it out," Dicks said Tuesday. "I'm kicking myself for doing such a stupid thing."

House rules prohibit lobbying groups from paying for congressional trips. Dicks said he believed the hotel and meals were being covered by Raydon Corp. (search), a Florida company that produces military training simulators. House rules allow companies such as Raydon to pay for congressional travel that is directly related to a lawmaker's fact-finding responsibility.

Dicks paid the $414 airfare to Florida himself. When he found out that Spectrum -- which Raydon had hired as a lobbyist -- paid for his hotel and meals, he decided to pay the full cost even though he could have asked Raydon to cover the expenses, Dicks said.

In an interview, Dicks called the episode a reminder that lawmakers need to be more careful about trips and who pays for them.

The issue has taken on urgency in recent weeks with House Majority Leader Tom DeLay (search), R-Texas, under fire for lobbyist-paid trips and other alleged ethical violations.

Dicks contrasted his behavior with DeLay's, saying: "There is no pattern of doing this repeatedly. We're not talking about large sums of money. We're talking here about one trip."