Geocoding recipe: locations not showing on Google Maps

Hi, can someone helpe me out with a Google Maps issue:

I’ve incorporated one of the recipes in Advanced Rails Recipes book (the
GeoCoding one). Although everything is done exactly as in the recipe,
the locations do not show up on Google Maps. (The geocoding part of the
recipe works - the Geokit has been tested on command-line and live).

For instance, here’s a search using the string “San Diego” and within 1

Exactly one gym is present in the resulting dataset, which is as it
should be - but it doesn’t show on the map.

This is probably some JavaScript quirk that just keeps avoiding me (a
relative newbie).

Here’s the part of the page that loads the map:

<% if @gyms -%>

<% end -%>