CentOS will not install on my Mac I am trying to install CentOS on another partition, and It will install, but every time, I get a GRUB HARD DISK ERROR.

Here are the steps I took:

•Resized Mac OSX disk and gave 20 gigabytes of free space (way overkill)

•Installed the net install on the a flash drive using unetbootin

•Booted off flash drive using rEFIt

•Selected HTTP installation, and plugged in the ethernet

•Entered the server


  Web site name mirror.centos.org
  
  CentOS directory/centos/5/os/i386


•Selected "Use Free space on Selected Drives" and selected the HD drive

•Selected the time zone and password

•Unchecked all of the features, don't want desktop GNOME

•Installation Completed, and Reboot

•rEFIt started up- boot linux from /boot 

•Black Screen with GRUB HARD DISK ERROR

Any suggestions for fixing this?

Thanks
I have experience this before trying to install backtrack Linux on windows. There is many program that can fix this problem just with a CD burn with a .ISO image. Try a program called "Super GRUB disk", it works for me.