98 landrover freelander 1.8 petrol?

hi, i have a 98 freelander , it has a 1.8 petrol engine, And its got a weird problem in that after starting it up ,it idles fine,. if you move it any distance it will over rev the engine quite violently and the car won,t move ,.Does anyone know if the engine over revving is not connected with the abs ,is it anything to do with sencors or does anyone have any idea what the problem might be,.thanks