Random craches with Webkit when surfing (probably something to do with QNetworkReply?)

Hello.

Compiled my browser project against Qt 5.3.0 beta and then tried to
do some surfing.

After some time it will always crash when loading page.

Running the application with QtCreator Debugger was
not helpful at all (Im on windows 7 and have no gdb or other debugging tools installed).

It just spew disassembler stuff.

However, looking from given output (please see the attached image)
it seems that this has something to do with QNetworkReply.

Also, sometimes the QtCreator prints the following lines:

QIODevice::write: device not open
QIODevice::write: device not open
QIODevice::write: device not open

And sometimes:

QIODevice::write: ReadOnly device
QIODevice::write: ReadOnly device
QIODevice::write: ReadOnly device

My project (http://sourceforge.net/projects/cyberdragonbrowser/) worked
with Qt 5.2.0 fine.