expand/collaps item problem in IE6

I download Jquery menu 6.x-3.0 and it works fine in firefox, but in IE6, the plus sign look bigger and the position is not proper either, also, if I click the plus sign, it expand but no minus sign, also there is another plus sign beneath the one I clicked, I must move my cursor over it, the beneath the plus sign can go away, otherwise, it is always there. I am sorry I am new to drupal, can someone help? Thanks!