I have two wordpress sites where the menu was popping up correctly
on one and not on the other.
Even though my twenty-ten themes are unmodified,
I tried adding the lines in the heard and footer - NoGo.
Tried disabling a few new plugins - and poof it worked.
Narrowed it down to: WP DoNotTrack, Version 0.8.3
Disabled that plugin, turned the other ones back on
and now everything is fine.