set up eclipse for roller

[AJ Chen]

I downloaded roller 2.0 source release and I'm trying to set up a roller 
project in eclipse directly from loading the build.xml.  Every java 
class can be build except for one:
public abstract class BasePageServlet extends VelocityServlet
It's certain org.apache.velocity.servlet.VelocityServlet is imported. 
The error message is a bit odd:
The type javax.servlet.http.HttpServlet cannot be resolved. It is 
indirectly referenced from required .class files.

Any idea how to fix it (build roller java files in eclipse)?

Thanks,
AJ