This documentation has not been updated for version 2 of the release.
The command line format has changed significantly.  My suggestion is
that you read the man pages for the old version to learn of the
operation of the program, and then run the program without parameters
to get a usage summary to see the new command line arguments.  Most
commands take a form similar to:

    Usage: snmpwalk -v 1 hostname community [objectID]      or:
    Usage: snmpwalk [-v 2 ] hostname noAuth [objectID]      or:
    Usage: snmpwalk [-v 2 ] hostname srcParty dstParty context [objectID]

You will most likely want either:
snmpwalk -v 1 hostname public ...   or:
snmpwalk hostname noAuth ...