in fire bug i see many 500 server error messaages on trying to post to the file:
http://www.rsavvy.com/io/google_javascript/promaps_geocache_php.php
that file is used to generate a cache of addresses so the map does not have to post to the google geocoder every time the page loads.
It is probably a permissions error. using File Zilla or another FTP program, change the permissions on the google_javascript/ folder and all files under it to 755