@CWatkinsNash: it sounds like extension-to-app mapping on your tablet has been corrupted in some way. The oracle of google finds reports of this happening if apps are selected to be the default for a mimetype (extension), then uninstalled.
Things I would try:
- Go to settings -> apps -> Moon+ and check what is in the "Launch by default" setting. It is probably empty, but it is worth the check.
- Reinstall the other readers. For each one, verify that it is not the default reader app for that type (same as above). I think you will find that your tablet "remembered" some setting. Clear all the "launch by default" for each app. Then uninstall again. While they are installed you might also check if CC finds any of these apps, just to verify that android "intent" mapping works at all on your device.