Can you use the usb key to boot your OS X installation? (select usb key at bios boot menut -> hit tab at the chameleon boot prompt -> select your internal hdd that you installed OS X on and hit enter).
From there open myHack app, select 'Install Chameleon' option and target your / partition.
This should fix the problem, if it does not you could try using myHack from the utilities menu on the OS X Installer, run "install chameleon' option, target the volume that contains your OS X installation.
If neither of the above fix your bootloader on the internal partition let me know I could send you a beta that contains an updated Chameleon bootloader as well as some new installation routines that may help to resolve the issue if it persists.