eyedropper doesnt select color

eyedropper / colour select troubleshoot
not too sure where i should post this but here goes…ive been using blender since 2.49. but i have never been able to get the eyedropper to work. whenever i click on the icon and then left click a colour it just turns black. i recently saw a tutorial about texture painting in 2.58 and it said you can right click to pick a colour. again this just turns the colour black. its v frustrating. either theres an option im missing or some setting on my laptop thats preventing it working. any help would be great. pls. http://bafull.cgcookie.netdna-cdn.com/images/smilies/sago/smile.gif

im using 2.58 on a windows 32 vista toshiba laptop