Or the minified version of the file...
<script src="angular-route.min.js"></script>
More information about this here:
"This error occurs when a module fails to load due to some exception. The error message above should provide additional context."
"In AngularJS 1.2.0 and later, ngRoute has been moved to its own module. If you are getting this error after upgrading to 1.2.x, be sure that you've installed ngRoute."
Listed under section Error: $injector:modulerr Module Error
in the Angularjs docs.