I have a similar problem. first of all, thanks for the amazing plugin!
The problem that I am facing is that sometimes the map is shown correctly, and sometimes it isn't shown at all (allthough the <div> IS shown!). If I look at the sourcecode (using Firebug) when the map is shown correctly, the sourcecode is:
<div id="ngg_geo_map_734" class="ngg_geo_map MSVE_MapContainer" style="width: 600px; height: 400px; overflow: hidden; background-image: none; background-color: black; cursor: url("http://ecn.dev.virtualearth.net/mapcontrol/v6.3/cursors/grab.cur"), move;">
When the map is NOT shown, the sourcecode is:
<div id="ngg_geo_map_407" class="ngg_geo_map MSVE_MapContainer" style="width: 600px; height: 400px; overflow: hidden;">
As you can see, a few arguments are missing when the map isn't shown, especially the url.
Is this a timing issue?? Seen the fact that the sourcecode is sometimes correct??
Thanks in advance!
By the way, I am using the twenty eleven theme (with a child template).