This most likely isn't a problem with NextGEN, its more likely a problem with Google Analyticator, but I thought people should know.
With Google Analyticator activated, NextGEN will fail to create thumbnails. I had several plugins activated including the aforementioned Google Analyticator and several NextGEN features were non functional. It screwed up the admin panel for one and broke thumbnail creation. I'm assuming at this point, it could affect other functions as well.
At first I assumed it was something funky with my server setup and the latest version of NextGEN, but after rolling back several versions I was able to rule that out. After that I disabled all my plugins except NextGEN and reactivated them one at a time... viola. The Google Analyticator plugin was the culprit.