(a) On application of a party, the court shall vacate an award if
- (1) the award was procured by fraud or other undue means;
- (2) there was evident partiality by an arbitrator appointed as a neutral or corruption in any of the arbitrators or misconduct prejudicing the rights of a party;
- (3) the arbitrators exceeded their powers;
- (4) the arbitrators refused to postpone the hearing upon sufficient cause being shown for postponement or refused to hear evidence material to the controversy or otherwise so conducted the hearing, contrary to the provisions of AS 09.43.050, as to prejudice substantially the rights of a party; or
- (5) there was no arbitration agreement and the issue was not adversely determined in proceedings under AS 09.43.020 and the party did not participate in the arbitration hearing without raising the objection.