I also have a Lenovo G530, and the touchpad is super sensitive. I experienced the same problem as you, with the cursor jumping all around the screen, simply from the weight of my hand on the palm rest of the laptop.
My solution was a bit different, however. I did NOT change my keyboard config (I left it set for the default that the installer put there for it). Instead, I turned off the touchpad, and I rely on a wireless optical mouse. The mouse gives me finer control than the touchpad, anyways.
To turn off the touchpad, enter the following in terminal:
Once I did, then there was no more jumpy mouse cursor on the screen, and everything works as it's supposed to.
To make things simpler, I created two simple bash scripts. The reside in my /home directory. One is called "TouchpadOff" and the other is called "TouchpadOn", just in case I should ever want to turn the touchpad on again. I then placed a symlink to "TouchpadOff" in my .kde4/Autostart folder, so it is ran every time I boot my computer.
I hope this is helpful to you!