It works for me (running OOo 2.3.1 on XP). And it seems like a rather useful macro for writing sciency stuff.
Did you follow the instructions on that page to install it? Go to Tools -> Extension Manager... -> My Extensions -> Add
It doesn't seem to matter where it is saved, I presume installing it will copy it to the correct place.
(and on an OpenOffice note, I notice v3.0.0 has just been released)