In your spring context xml mvc namespace url should match url in schemaLocation. Something like this:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">
This is a standard XML namespace declaration. The namespace url is sort of an unique id, which is then mapped to the actual schema location in xsi:schemaLocation.