Okay, that error means that you ARE contacting the Tomcat server - i.e. tomcat is running for you.
What you probably do NOT have correct is the tomcat configuration file. The "context" that's being referred to is the web application context. For example, if I have a JSP application called "MyApp", I generally will get to it through the URL of:
http://myserver.mydomain:8080/MyApp/somefile.jsp
"/MyApp" from the above URL is called a "context" in Tomcat.
A full-blown installation with all the bells and whistles will often define a context of "/" that gets you to a default Tomcat welcome page - but it doesn't have to. See if you can deploy a simple JSP application. If it works, then you're set.