I receive a 'Package file is invalid' Error when installing or upgrading FreeTone for Android. How can I fix this?

(Android)

This is an error that some Android users get when installing applications for the first time or when upgrading applications in the Google Play Store.

The error can happen with any application downloaded from the Play Store and is not specific to TextMe. (See confirmation from Google)

Unfortunately, there is not a single fix to resolve this issue, but rather a series of actions that should be tried until the installation succeeds. The following steps could be tried until the problem is resolved:

Fix 1

1. Go to Application Manager: Phone Settings -> Applications -> Manage applications. (On newer phones, go to Phone Settings, press More at the top and select Application manager) 
2. Select Google Play Store Press "Clear data" and "Clear cache"
3. Go back to Application manager  Select Google Play services Press "Clear data" and "Clear cache"  
4. Try to install or update FreeTone again from the Play Store

Fix 2

1. If that doesn't work Go to Application manager (as in Fix 1)
2. Select Google Play Store Press "Uninstall updates"
3. Try to install/update FreeTone again from Play Store

Fix 3

1. Some users report that removing and re-adding their Google Account fixed the problem
2. Go to your Phone Settings, then Accounts, the Google
3. Remove your account and re-add it. 

Fix 4

1. Users updating an existing installation can try the following: Go to Application Manager: Phone Settings as in Fix 1
2. Select FreeTone Press "Clear data" and "Clear cache" (Warning: You will lose all your FreeTone messages)
3. Try to install FreeTone again from Play Store