Replying to NS Linux Geeks?

I know there are a few of you out there!

I'm biting the bullet and finally dual booting my macbook pro 5,5 with Fedora.  I'm having a little difficulty with the boot loader.  Basically an error comes up during install saying boot loader mounting was sketch and 9 times out of 10 it stalls after rEFIt.  Almost every walk through I can find is for Ubuntu or Mint.. which don't really help much.  I'm also trying to make a bootable external hard drive so I can use basically any computer. 

Any help would be greatly appreciated!

The only program I need to run is openFOAM which only comes pre-compiled for Fedora or Ubuntu.  I would love to use another flavour of Linux but don't really fancy compiling the source code myself..