Trouble Mounting Partition

I have been prepping my laptop (Asus G50v) for the installation of OSX 10.6. I have been trying to follow the how to which is stickied within this forum section. However, when i try to mount the partition which holds the retail_disc.dmg, or even the partition which i will be installing snow leopard on, i get an error which says the partition is unmountable, and i need to run first aid on the partition..

I am currently running four different operating systems, here is my partition table:

sda1 | Windows Seven
--------sda2-----------
sda5 | /boot Ubuntu
sda6 | /Ubuntu
sda7 | /boot Fedora
sda8 | /Fedora
sda9 | /Backtrack
-------------------------
sda3 | Shared Drive
sda4 | Snow Leopard

I currently have the retail_disc.dmg file on a portable hard drive (which disc utility recognizes, but wont mount), if that matters. I have tried using FAT32 file system, as well as NTFS, and still no luck!

I have been following this tutorial as well:
http://www.insanelymac.com/forum/index.php?showtopic=18… ↗

Thanks,
Ben