Brush tool doesn't work

I have just downloaded Photoshop Touch to my Samsung Galaxy Tab 10.1 which is running Android 4.0.4. The brush tool doesn't seem to work. I was wondering if this software is supported on this tablet.

Hi. I'm sorry to hear that you have problems using the brush tool. Unfortunately I'm not able to reproduce – see my attached screenshot.
When you compare the attached screenshot with the result on your device what difference are you seeing?