source

If you installed XFree86-Version 4.0, the configuration has to look like


File /etc/X11/XF86Config
Code:

  Section "InputDevice"
      Identifier "Mouse"
      Driver     "mouse"
      Option "Protocol"        "imps/2"
      Option "Device"          "/dev/psaux"
      Option "ZAxisMapping"    "4 5"
      Option "Buttons"         "3"
  EndSection
I'm finding the same thing as you. Have you restarted the Xserver?