Seems like your "initial ramdisk" - the basic OS which is used to boot the system further - is corrupted. I suggest booting from a Live-CD, Install-CD or something such and replacing it.
You might find some explanation why this has happened and how it is corrected
here and
here, a general explanation of how to debug Dracut problems can be found in the
Fedora Wiki.
All these links came up on top of a Google search for "Dracut warning", directly copied from the error message you posted. The best help i could give you therefore is: don't be shy, paste errors simply into Google and usually something helpful comes up.
I hope this helps.
bakunin