first thing: do you have a wheel mouse or a three button mouse?
for Option "Protocol" "ImPS/2" i believe that is for Wheel mouses only (someone correct me if i am wrong)
if you already have three buttons then you don't need to Emulate3Buttons. make this option false
you can reconfigure your x system by using this command
make sure that you have all of the specs on your mouse, keyboard, vid card, monitor.
hope this helps