Question [Q] Can't restore back to stock rom

I made backup with cwm before installing custom rom. And then, accidentally, once again I made backup of the rom. So I deleted the latest backup from file manager. Now I want to revert back to stock but when i choosing the backup file its saying 'md5 Checksum mismatched'.

I searched about this and get across a thread about this problem (link)

I followed mentioned commands in thread using adb:

adb shell
# cd /sdcard/clockworkmod/backup/2010-06-
# rm nandroid.md5
# md5sum *img > nandroid.md5

Now on the last command adb saying that 'md5sum not found'. cant figure out the problem.

One post I saw somewhere told me to install busybox and try command '# busybox md5sum *img > nandroid.md5'. But that also gone in vain.
If I am helpful, press the thanks button!!