QT4 Touch Screen hangs when touch screen is touched with 2 fingers!

Hi all,
1) I am using QT4 for embedded and I have written an app for my TS device. So far, it works just fine when only one finger is used to press the buttons, but when I touch the TS with two fingers and release at the same time, my TS stops responding. It's seems like the touch screen locks.

2) The only way to unlock this is by again touching the TS with two fingers, releasing one finger while still touching it with another one and then releasing the second one too.

After this, the TS starts working just fine. Looks like I am not handling an exception. How do I go about it? Any help would be very much appreciated!

Thanks!!