Hey everyone, thanks for replying!
I have managed to locate the XDK files, and obviously they are not .xbe files, they are .xbx files. I would flash the BIOS but I have looked all over this forum about flashing the BIOS on a softmodded XBOX and everyone is saying not to do it as it will screw the XBOX. My box is already softmodded, and I have to say its AWESOME! (Thanks to all the people who made this possible!)
So, going back on topic, so as obcd said, a modded XBOX can run the PBL no problems, (Bear with me, I'm a little bit of A newb, I know we can be annoying sometimes!!) So to load the PBL on my XBOX i just FTP it into my apps folder and it will run without any installations or flashing required? or is it an auto installer that needs burning onto a disk? and once PBL is running, Do I just select the default.xbx file from the XDK folder?