I have this strange problem with my widgets moving to the left side of my screen whenever I reboot or log back in. It seems that this problem disappears if my widgets are left unlocked.
Here is a screen shot:
I called upon past experience and deleted my .kde4 directory, but this has no effect. I then decided to do a clean install of the KDE 4.2 Live CD on a completely clean partition setup. Suffice to say, only leaving my widgets unlocked results in my widgets maintaining the correct position.