Apparently something has to be loaded to use whitespace-global-mode.
My emacs knows nothing about it.
C-h i <RET> m <RET> i whitespace-global-mode <RET>
Info doesn't know about it either.
Finally:
grep -r whitespace-global-mode /usr/share/emacs/23.1.50
Shows the name has been aliased to:
usr/share/emacs/23.1.50/etc/NEWS.22:***
`global-whitespace-mode' is a new alias for `whitespace-global-mode'.
M-x load-library <RET> global-whitespace-mode
Loads the source file... but still setting the check call fails here:
M-x whitespace-toggle-s<tab> fails to find anything
Maybe more names are changed?
What version of emacs are you running.