The game was most likely updated and your files might have gotten corrupted.

Please try the following steps:

1. Go to: Settings -> Applications -> SF Girls -> select Force Close

2. Go to: Settings -> Applications -> SF Girls -> select Clear Data

3. Uninstall the SF Girls app

4. Reboot your phone

5. As soon as your phone starts, direct your browser to Nutaku to download the Nutaku Android Client for automatic game updates.

Although we do not recommend this, you can directly download the game from the link below, but you will have to update it manually and this might cause bugs if you continue using an outdated version.