Bootcamp on mac - Partitioning error

Hey

I was trying to install Bootcamp on my mac but I kept getting this message when I was partitioning my disk, "The startup disk cannot be partitioned or restored to a single partition." I tried pushing command-r and running disk untility and repairing disk. That didnt work. Do you have any solutions for this. It is really annoying and I cant figure out why it doesnt work.

Thanks

Armoured-Bear