logitech quickcam zoom

hi there got a slight problem. switched from pc to mac mini and have a quick cam zoom form logitech. although it says on their internet site that it works with mac it does not unfortunately. I did download the drivers for mac and installed them but when I connect the cam and open yahoo it always says it can not find a webcam. however on logitech's site it says it should work with yahoo messenger....
can anyone help me?

tom