Running Drupal 7.22
Trying to upgrade from GMap 7.x-1.x-dev to 7.x-2.6.

I can't get any of the clustering libraries to work on the new version of GMap. JavaScript libraries are installed as they should be. When set to "No manager" the map points show up as they should. Trying to use any clustering manager causes a blank map... zooming, etc. doesn't fix it. If I revert back to my previous version (7.x-1.x-dev with ClusterMarker) it works fine again. I've dug into everything I know how to, but can't find the problem.

How can I get clustering to work in 7.x-2.6?
Thanks!