Skelton delayed the general's testimony by a few minutes so the problem could be fixed.
During opening statements, Rep. Tom Lantos, D-Calif., said the men had come to Congress to "restore credibility to a discredited policy."
But, he said, "with all respect to you ... I don't buy it," Lantos said.
"We need to get out of Iraq, for that country's sake and for our own," Lantos said.
Rep. Duncan Hunter, R-Calif., said "it's an outrage," that unnamed Democrats were attacking the general's credibility in advance of the nationally televised hearing.
Answering charges that his testimony was screened by political officials within the Bush administration, Petraeus countered, "I wrote this testimony myself. It has not been cleared by nor shared with anyone in the Pentagon, the White House or the Congress."
The general's testimony could be key to the White House's attempt to stem a rising tide of Republican dissent over Iraq.
The Democratic-led Congress currently doesn't have enough votes in Congress to force President Bush to begin withdrawing troops from Iraq -- but that could change if more members of Congress are persuaded the President's Iraq strategy is failing.
The general came under personal attack Monday by the anti-war group MoveOn.org, who took out an ad in The New York Times on Monday. "General Petraeus or General Betray-us?" read the ad.
"Cooking the books for the White House," it said.
Independent Connecticut Sen. Joe Lieberman slammed the ad, saying in a statement, "We must reject the slander of this brave soldier and patriot." The 2000 Democratic vice presidential candidate went on to call the ad "an outrageous and despicable act of slander."
White House press secretary Tony Snow also chimed in, labeling MoveOn's effort "a boorish, childish, unworthy attack," and called on members of Congress to condemn it.
"I don't want to want to insinuate that there were never conversations between General Petraeus or the White House and so on. But when it comes to this testimony, we have stayed out of it," Snow said Monday. "We have let General Petraeus and Ambassador Crocker do this independently and we have not tried to play any role in shaping, in influencing, in dictating, in doing anything with regard to the content of what they do."
While details of Petraeus' assessment of President Bush's troop escalation plan leaked in media reports last week, his actual testimony has been a closely guarded secret.
The general did not share his testimony or opening statement with the White House or Congress, according to his staff. Nor did he share his testimony with the Pentagon.
In an exclusive interview, the top military general in Iraq hinted to ABC's Martha Raddatz that his report on the status of the troop surge in Iraq would include a recommendation for troop reduction in March, if not sooner, to avoid a strain on the Army.
Monday is the first hearing on Iraq for Petraeus and Crocker, and begins a weeklong focus on the future of the Iraq conflict.
The pair are scheduled to appear in a prime-time interview with Brit Hume on Fox News Monday night, and will testify before Senate committees on Tuesday. They hold a news conference and conduct interviews with network anchors on Wednesday.