OK, before blindly installing this I wanted to know what the fix indeed does and unpacked it and examined the content.
HTC seems to be developing on this cause the package name is: Hotfix LEO08787_1.5
what indicates that there might have been some minor versions earlier
So I discovered, that it indeed replaces a driver file
Guess what? It's the "touch.dll" with a new version (20100319-00)
It places two strings in registry
So thats it for now.
I attach the extracted file only for personal use.
I take no responsibility for unresponsive touch screens.
Be aware that you know what you are doing be using this.