Make sure the following images that are referenced are uploaded to your server:
var icon_0 = new GIcon();
icon_0.image = 'plugins/google_javascript/images/traditionalpillow_deepjungle.png';
icon_0.shadow = 'google_javascript/images/traditionalpillow_shadow.png';
icon_0.iconSize = new GSize(34,35);
icon_0.shadowSize = new GSize(34,35);
icon_0.iconAnchor = new GPoint(9,33);
icon_0.infoWindowAnchor = new GPoint(19,0);
icon_0.printImage = 'plugins/google_javascript/images/traditionalpillow_deepjungle.gif';
icon_0.mozPrintImage = 'plugins/google_javascript/images/traditionalpillow_deepjungle_mozprint.png';
icon_0.printShadow = 'google_javascript/images/traditionalpillow_shadow.gif';
icon_0.transparent = 'google_javascript/images/traditionalpillow_deepjungle_transparent.png';
Check the google_javascript/images directory on your server to make sure they are there. If they are not, make sure you upload them to that location.