Reinstall Mac OSX on Ubuntu Macbook
You can't install Mavericks on a 2006 MacBook.


  To install Mavericks, you need one of these Macs:
  
  
  iMac (Mid-2007 or later)
  MacBook (13-inch Aluminum, Late 2008), (13-inch, Early 2009 or later)
  MacBook Pro (13-inch, Mid-2009 or later),
  MacBook Pro (15-inch or 17-inch, Mid/Late 2007 or later)
  MacBook Air (Late 2008 or later)
  Mac mini (Early 2009 or later)
  Mac Pro (Early 2008 or later)
  Xserve (Early 2009)
  


Source: http://support.apple.com/kb/ht5842