Need help with Mac os X


Hi, i partitioned my comp into 2 using acronis, vista is my primary active OS.
When i try to install MacOSX i.e. put DVD in and restart comp and goes into Darwin loader and then goes to the apple sign then it reboots back to the darwin loader screen does anyone know whats wrong or what is happening? When i hit F8 the only thing i can see highlighted is my 111GB which where my vista is installed, it seems that it doesnt recognise the other 50GB that i left for MacOSX so when i press enter it does the same thing and goes back to the darwin boot screen.