I got this solved.
But here is the question and the solution.
SQL ERROR [ postgres ]
ERROR: null value in column "challenge_id" violates not-null constraint 
INSERT INTO phpbb_arcade_challenge (challenge_points, challenger_id, opponent_id, game_id, challenger_game_cost, opponent_game_cost, challenge_time) VALUES (0, 2, 55, 227, 0, 0, 1358351919)
FILE: (not given by php)
LINE: (not given by php)
I had to edit the challenge_id column edit defailt value (there was nothing in it). This is found in the Control Panel at Lunarpages PhpPgAdmin
Sorry for the edit.