First:
1. What version of AppGameKit are you using?
2. Where did you get your Android Player?
Next, any files that your app needs to upload should be in the <project>/media directory, not in the Documents path.
If your app creates or rewrites any files, then they show up in the appropriate sandbox area for the device and will be read from there after that.
When using the player, any such files end up in the Player's sandbox area and may or may not be available the next time.
Cheers,
Ancient Lady
AGK Community Tester and AppGameKit Master