jboss- Missing classpath entry

In Eclipse, I'm trying to create a new 'dynamic web project' by going to New->dynamic web project. As I start entering the Project Name, I get the following error: Runtime "JBoss v5.0" is invalid. Missing classpath entry C:\Program Files\JBoss\bin\run.jar

Snapshot:

I'm using JBoss version 5.1.0-GA. Please help me with this.