@MakaMika Sorry to say but you can join us here http://forum.xda-developers.com/show....php?t=2540950
Anyway, still some chance to fix this touch screen problems with a software, a good new FW which we wait for it but I will not wait until that and I will send the phone back to the store when you bought it a tell them to fix it or replace with a new device, like I did. The phone still under warranty and should be issues free and it's not so you have the rights to send it back. Sony Service will decide if repair or replace.
My problem occurs even when browsing pictures, swiping in the pattern lock and gaming especially Shooting games like CK2