It's subscriber access only, but here's the salient part of The Rubbishing of Haiti's crucial vote.

The question now hovering over Haiti is what lay behind the confusion over the count: fraud, or just chaotic inexperience in a failed state with an almost non-existent democratic tradition?

In earlier talks with UN officials, Mr Préval had insisted on a thorough, internationally verified review of the count. In response, the government offered an inquiry, but one which excluded outsiders. [P6: emphasis added] That added to suspicions. The secretary-general of the Organisation of American States flew in to try to resolve the dispute. Brazil, which heads the UN peacekeeping mission, pressed for Mr Préval to be declared the winner. Diplomats at the Security Council in New York insisted that UN officials be involved in the review. 

...The problems arose after votes had been counted at the polling stations. According to Gerard Le Chevallier, who heads the UN election team in Haiti, many of the tally sheets were incorrectly filled out by poll workers.

As a result, the electoral authority invalidated almost 150,000 votes, many from the capital’s slums. That hurt Mr Préval, not only because he was strong in those areas, but because 50% of all votes, including blank and spoilt ones, were required to avoid a run-off. Similarly, many questioned whether at least some of the 85,000 blank votes had not been stuffed into ballot boxes to stop Mr Préval. In addition, tally sheets for some 8% of the ballots disappeared, some when party activists attacked polling stations in the interior. Mr Préval’s supporters found thousands of burned ballots still smouldering on a rubbish dump in the capital.

I can't help but feel there were other ways to get the input and influence Mr. Preval's opponents want.