We're aware of the issue but there isn't a workaround.
We have fixed this for the next release of the API (3.8) which will be out in the next two weeks or so.
... dojo.connect(map, "onMouseWheel", mouseWheelHandler); ... function mouseWheelHandler(evt) { var intDelta = evt.wheelDelta; try { if (intDelta < 0) { map.setLevel(map.getLevel() - 1); } else { map.setLevel(map.getLevel() + 1); } } catch (exp) { console.debug(exp.Description); } }