Kernel panic lfs 6.8 linux 2.6.37.2

help me
kernel panic
This is the message,

no file system could mount root, tried Ext3 ..
kernel panic - not syncing : VFS: unable to mount root fs on uknown - block (8.22)
pid : 1comm : swaper not tained2.6.37.2 #1
....
....
....
.... auto stop usb root hub
usb usb5 : suspend_rh (auto stop)

lfs6.8 I compile and install using lfscript4revision12 into an ext4 partition without creating an iso
I boot with ubuntu's grub!
used ext4 partition,
I question what the problem is and what is the solution?
what's the problem in type partition or kernel or something else?

lfs6.8 with kde base