Note sure of your Eclipse version. In 4.2, Select Window>Open Perspective>Other... and then CVS Repository Exploring. In the "CVS Repositories View", right click and select New>Repository Location....
- Connection Type: pserver
- User: anonymous
- Host: tolven.cvs.sourceforge.net
- Repository Path: /cvsroot/tolven
- Use default port
Click on OK. You should see something like this:
You're going to want this to be an Eclipse Java Project. So create a Java project with separate source and binary folders. In the "CVS Repositories View", right click on the stuff you want to edit in Eclipse and select Check Out As.... Select ...into an existing project, then Next>. Now select the source folder of the Java project you just created. and Finish.
You're probably going to want to move the non-Java files, but this gets the Java source in the right place.