Problems with android app

I have 2 problems with the android app.

1. When my Voipo number is called, the mobile phone shows that a call is coming in from Voipo. The ringtone is much too loud and I can't find a way to set the volume. Also, I can't find a way to select a different ringtone.

2. When I go into settings and choose touch "preferences", the app give me a "Unfortuantely, VOIPo has stopped". I assuming that I might be able to set up maybe a different ringtone and set the volume of the ringtone here, but preferences does not work.