You can use it on that board. Just because it is "Designed for Intel P67 motherboard" doesn't mean it won't work just fine on a Z68 board. Also on the newegg page for the RAM it says the following under "features":
"Designed for 2nd Generation Intel Core Processors and the Z68/P67 motherboards Optimized 1.5V low voltage for the Intel Sandy Bridge platforms Compatible with Intel P55 & AMD Phenom II/Llano platforms Intel XMP ready"
So you should not return it because it will work fine with your board. By the way, the link for the RAM is bad, but I found the page by searching for it.