In his first and only season at Go Ahead, Kokmeijer was seriously injured by opponent Rachid Bouaouzan playing for Sparta Rotterdam on 17 December 2004. Kokmeijer's leg was broken badly and he was forced to retire from professional football. Sparta Rotterdam suspended Bouaouzan for the rest of the season, which was more than the 10 match ban the KNVB awarded him. Besides that he was taken to court by the Dutch government and Kokmeijer for battery, a unique moment in Dutch football history. Bouaouzan received a suspended six-month jail sentence.