Generally when accessing a JSP I would expect a JSP extension on the URL. Something like "http://localhost:8080/helloworld.jsp" or the like. The exception to this is when the JSP is named index.jsp - Tomcat uses that name as a default when only the directory is specified.
To use Eclipse with Tomcat you'll have to start Tomcat with the JPDA. You will want to export the environment variables JPDA_ADDRESS=8000 and JPDA_TRANSPORT=dt_socket (those are the defaults) to enable this. Then, in Eclipse you can debug with the "remote application" method. You'll want to make sure your source and what Tomcat is running are the same thing.
I don't feel that this is a permission problem. Start with getting Tomcat working for a simple JSP page first. Then you should
be able to debug more. A warning though - JSP's are very difficult to debug if you are putting Java
code in them. If you call a bean or some other code from a JSP that is easy. But if you want to walk through a scriplet in a JSP that can be difficult. The reason is that a JSP is translated into a servlet
and then compiled. The translation generates a ton more code than your JSP has. Once your JSP is working take a look in the Tomcat work directory. That contains what Tomcat did to run the JSP.