Vote counting in the fierce congressional battle between incumbent Charlie Rangel and his insurgent challenger Adriano Espaillat is no longer a matter of the usual incompetence of the Board of Elections. Troubling signs have now emerged that some officials at the board crossed the line in an all-out effort by the Democratic Party establishment to ensure a Rangel victory, and that the board’s staff wrongly disqualified hundreds of paper ballots. Board officials began their tally Thursday of some 2,600 paper ballots. Those are either mail-in absentee votes or “affidavit” ballots from people who went to the polls last week but were told their name was not on the rolls. That count showed Rangel increasing his slim 807-vote overall lead by another 131 votes, although Espaillat’s main base area of Washington Heights and Inwood has yet to be counted. But until now, no one has mentioned more than 2,000 additional paper votes the board’s staff tossed out this week as invalid.