I even uninstalled and reinstalled the whole game to be sure there were no corrupt files or anything like that.
When moving from one beta to another, I uninstall Elemental, then also delete the "\Documents\My Games\Elemental" and "\Program Data\Stardock\Elemental - War of Magic" directories that the uninstall doesn't remove. Then I reinstall.
I'm not saying that this will fix your problem, just that it's been recommended as a good practice to follow when participating in the Beta.