Hmm maybe your drive isn't set to active.
Plug it into your mac and do the following:
1. Find the the disk & partition numbers by ether typing
in Terminal or right clicking on the parition in Disk Utility and selecting Information. It should look something like
disk1s2 where the first number is the drive and the second is the partion.
2. Then open Terminal and type the following text in green. Pressing enter for each line (Remember to replace the numbers below with those you found from step one.):
fdisk -e /dev/rdisk1 - Replacing "1" with your drive number
p
f 2 - Replacing "2" with your partion number
write
y
exit
Guys feel free to chime in with an easier method or other solution.
I don't remember if you said you were wanting to dual boot or just install OSX?
Please do not PM a copy of your latest post as I subscribe to the threads i post on.