dual boot on GPT error

[howoarang]

Hi, I will try to install Mac OSX Snow and Windows 7 on the same disk with 3 partition, which is formated as GPT disk. So if I tried install Windows 7 to this disk, get error "systam can not be installed on GPT disk"
Can you help me how to make dual booting systems on my laptop dell d630 with one disk in GPT scheme?
Or only solution is format whole disk as MBR

Thanks