I am using Google Maps API to display a map on a certain page.
Problem is that the file http://maps.google.com/maps?file=api.....
sometimes happens to load
Use Google's Ajax APIs. From some time past, all of Google's services can be accessed through the JavaScript API. It's a modular system, you only have to include the JSAPI library, and then you can dynamically load the modules you need—it won't block your site.
For further details, see JSAPI's developer documentation.