用Fedora17制作了一个Livecd 的iso文件，用虚拟机启动后出现下面情况，该如何解决
[ok] started show plymouth boot screen
dracut-initqueue[180]:mount: unknown filesystem type iso9660
dracut-initqueue[180]:Warning
dracut-initqueue[180]:Warining: dracut FATAL:Failed to mount block device of live image
dracut-initqueue[180]:Warning: dracut: Refusing to continue
dracut-initqueue[180]:Warning: /dev/mapper/live-rw 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 aUSB stick or /boot
after mounting them and attach it to a bug report
dracut:/#_