grub v2.00 beta3 -"can't find command -s"

[Goh Lip]

Using grub v2.00 beta3, after editing menuentry using key 'e', I tried 
to boot either 'ctrl' +'x" or 'F10'. there is an error -  "can't find 
command -s" or "unknown command 's".

There is no problem if I boot using grub prompt (key'c') but that 
requires inputting all commands/parameters.

Can anybody explain or help how to edit?
Thanks.

Goh Lip