Why won't this Fandango App install?

Hi, I recently tried to update the Fandango app on my phone from Google Play, and the update got screwed up. When I restarted the update, after it downloads, it tries to install it, but gives me an error message like "package invalid" or something like that. I completely uninstalled the app, then tried to install it again, but still got the same error. I downloaded the .apk, and tried to sideload it, but it said cannot install app. I tried uninstalling and reinstalling Google Play Store, but it didn't work. I also tried clearing the Google Play data and cache, and I even tried wiping the cache partition of the phone, but that still didn't work. I have a ton of internal storage memory for apps left. I'm not willing to do a factory reset. Any suggestions? Thanks for your time!

Droid 2 (yes, 2) :-)
Gingerbread
Rooted