ibook display - cannot click in some areas and rendering error

I'm having a really strange effect on my ibook display. There is a small area, about 2x2 inches to the lower left of the display, where I can not click with the mouse AND safari produces a rendering error while scrolling down. The rendering error: In the area mentioned the page does not scroll down like the rest of the display, so the rendered part in this area is offset by about a quarter inch. If I move the window the window to the right I can click the links again.
I have not found a suitable entry in mac forums. Anybody with a similar problem or a solution? Did anybody read of a similar effect and could provide me with a link explaining the behaviour or a possible solution. please help, it drives me nuts I attached 2 small screenshots of the effect if this might help.
big thanks
_Markus

Yeeeha - Big thanks & different way to solve it

GeeYouEye
I tried it and it works. thanks. http://www.loopnews.co.uk/macoshints.php told me how to edit the com.apple.dock.plist in /Users/<user>/Library/Preferences/ and change the Value for key "wvous-floater" back to "false". Restarting the dock and everything was fine again.
This is a good day. merci