A tabulation error has thrown in doubt the election night victory of Rep. Tim Bishop on Long Island and given Republicans hope that they may add yet another seat to their new majority in the House of Representatives. Officials in Suffolk County said the error, discovered Friday, shifted several thousand votes and erased Bishop's 3,500 vote margin. That put Republican challenger Randy Altshuler ahead by just under 400 votes in New York's 1st Congressional District. Bishop is seeking a fifth term in the district, which includes many of New York's beach communities.