zoomfactor jumps to 17

hi,

here is a problem i was struggling with,

1. loading the map API
2. setting map.centerAndZoom(new GPoint(0,30), 14); in order to see
somthing
3. load through XMLHttpRequest markers with infoWindowHtml
4. therein is a js-link calling a function that recenters the map to
the given point (passing the marker object id and a fixed zoomlevel,
mostly 3 for non high res areas)
5. that calls map.centerAndZoom() and executes fine

afterwards any other map interaction executed fine, EXCEPT zooming out
one step (by the "-"-symbol of GLargeMapControl or by calling
map.zoomTo(mMap.getZoomLevel() +1))

the reason: i didn't parseInt() the zoomlevel assinged in (4), executed
in (5) but comming from the XML parsing in (3). the setting of the zoom
as string seems to work but the relative ++ or -- calculations don't
work on that value anymore and get reset to max/min...

andré