Windows restore no longer finds Windows Image backup files.

If I boot the Windows 7 emergency recovery DVD it no longer finds any Windows image backups on my USB drive. I have tried it on 2 different Windows 7 PC's. I can however see the backups in the \WindowsImageBackup directory while booted from the DVD and going to the DOS prompt. The kicker is that I used these backup images before to replace hard drives on both systems. I do not know what changed. The search on the PC for the images takes only a couple seconds before failing. I have tried changing permissions and ownership on the files without success. Got any ideas?