ValueError kernel name must start with /boot/vmlinuz during the redhat-upgrade-tool

Issue

• After running preupg there is no issue shown and redhat-upgrade-tool gives error as ValueError: kernel name must start with '/boot/vmlinuz-.

Continue with the upgrade [Y/N]? getting boot images...
setting up update...
testing upgrade transaction
setting up system for upgrade
  File "/usr/bin/redhat-upgrade-tool", line 448, in <module>
    main(args)
  File "/usr/bin/redhat-upgrade-tool", line 369, in main
    upgrade_boot_args()
  File "/usr/lib/python2.6/site-packages/redhat_upgrade_tool/boot.py", line 169, in upgrade_boot_args
    '--update', kernelver(kernel)])
  File "/usr/lib/python2.6/site-packages/redhat_upgrade_tool/boot.py", line 32, in kernelver
    raise ValueError("kernel name must start with '%s'" % kernelprefix)
ValueError: kernel name must start with '/boot/vmlinuz-'