the problem on your other page is caused by mixing the Google Maps V2 api and the V3 api.
the code generated by design extender uses the google v3 api.
the code for your map:
<!-- MAP START HERE -->
<div id="map" style="width: 500px; height: 360px"></div>
<script src="http://maps.google.com/maps?file=api&v=2&key=ABQIAAAAtCqz5i2UepKpsK0jDA39uxTraGz99MIGniqCPhnwOuwIPEemEhSR3R45WE6M-VlfOoMJSmywoEfozQ"
type="text/javascript">></script>
<!-- MAP END HERE -->
uses the v2 api, and is causing a conflict.
if you remove that code from the page, the design extender map will start working.
you can use more than 1 V3 map on the page, but combining the 2 apis will cause conflicts.