Code:
action water()
{
	fx_mirrorWater();
	while(1) {
		if(key_hit("1")) terrain_raise(me,-0.5);
		if(key_hit("2")) terrain_raise(me,0.5);
// skills are defined as var, but shaders use float values 
// conversion is not automatic here, thus we need floatv/fixv
		if(key_hit("3")) my.skill43 = floatv(fixv(my.skill43)-5);
		if(key_hit("4")) my.skill43 = floatv(fixv(my.skill43)+5);
		if(key_hit("5")) my.skill44 = floatv(fixv(my.skill44)-5);
		if(key_hit("6")) my.skill44 = floatv(fixv(my.skill44)+5);
		if(key_hit("7")) mtl_hdr.skill2 = floatv(fixv(mtl_hdr.skill2)+1);
		if(key_hit("8")) mtl_hdr.skill2 = floatv(fixv(mtl_hdr.skill2)-1);
----------------->>>>>> water_height = terrain_get_z(my,1);<<<<<---------------------------------------
		water_ripple = fixv(my.skill43);
		water_scale = fixv(my.skill44);
		hdr_threshold = fixv(mtl_hdr.skill2);
		wait(1);
	}
}


yeah only one i can find too , have you assigned this action to a block or something ?

Compulsive compiler