How to resolve dracut problem when intall Fedora 21

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I'm Ubuntu User. But I wanted to change my OS from Ubuntu to Fedora. So I wanted to Fedora 21. But there is a problem. I'm using USB Drive to boot Fedora 21. When I try to install Fedora I get a error.

dracut-initqueue[109]: Warning:    Could not boot.
dracut-initqueue[109]: Warning /dev/disk/by-uuid/66fad037-3a77-4ef1-ac36-3b20262dbec7 does not exist
    Starting Dracut Emergency Shell
Warning: /dev/disk/by-uuid/66fad037-3a77-4ef1-ac36-3b20262dbec7    does not exist

Generating "/run/initramfs/sosreport.txt"

Entering emergency mode. Exit the shell    to continue.
Type "journalctl" to view system logs.
You might want to save "/run/initramfs/sosreport.txt" to a USB stick or    /boot
after mounting them and attach it to a bug report.

dracut:/#

So Ca you Tell me who to resolve this problem? Because I'm Stuck.