Yup, I've had exactly the same problem. However, I didn't solve the problem, my mouse did by breaking and forcing me to replace it

Without knowing what mouse you have etc its difficult to solve the problem, but you are likely to have some software that controls its functions. I'm guessing, but I suspect that you need to adjust the sensitivity of the scroll wheel.

I hope someone can give more positive advice

Ill go look out the floppy driver disk the now  

See if that fixes it.

Big_boss your mate Robotochan was here on the weekend with another problem with a Chic mouse.

He eventually solved his problem by hitting the mouse on the desk

I don't know, perhaps these Chic mouses respond to violence  

Hmm think ill try reasoning with it first. If it complies alls well, if it doesnt then.... who knows what could happen  

I wont be help responsible 8)

I wonder if they just wear out after a while?  I tend to try to keep the bottom of mine clean, especially the sensor, or it starts playing up.  Perhaps there's some dirt in the wheel?

Try looking at this article there is a section part of the way down about flickering

Are you using the mouse as PS/2 or USB?

It looks very similar to my Typhoon optical one BB.Have you set it as a 3 button or 5 button mouse and have you got the options for each one set correctly?
Cant think how you could set the wheel do do as you describe but it may be something as silly as that