hmm ur using gamemaker 1.4, havent used that in a while. Are you using drag and drop for the screen wrapping? I suggest using code instead. here try this:
//not sure how ur doing movement, but this should work regardless. Just remove the "x+=move_speed;" if ever ur using a different method for moving. the important part is the Wrap()
Step Event:
x+=move_speed;
x=Wrap(x,0,room_width);
Script:
function Wrap(_value, _min, _max){
var _range=_max-_min;
while(_value>=_max) _value-=_range;
while(_value<_min) _value+=_range;
return _value;
}