ccorner,
It sounds like you're making things harder for yourself than you might need to. Are you really trying to use three programming languages (python, tcl/tk, and java) all at the same time?
I can't tell whether you're struggling with getting IDEs installed, or writing a simple program, or calling the Echo Nest API. But maybe back up a step and start simple. You say you want to write a program in Java, so start with just writing a "hello world" Java program using whatever text editor you have on hand and the command line for invoking the compiler and JVM. If you can do that much, it proves that your Java development environment is set up properly, which is a good start.
From there, maybe you want to use a graphical IDE (like IntelliJ). OK, install that, and make sure you can create and run a "hello world" style program inside that IDE. Still no Echo Nest anywhere in sight.
Once that's all working, you'll need to figure out how to make your program one level more complicated and start depending on a third-party library like jEN. So download the jEN JAR, add it to the classpath for your project, and try doing something trivial with it. Maybe instead of printing "Hello World", call artist/news and print out the latest headline about Justin Bieber or some such thing.
If that works, it means you're set to call our API properly, and you can start in on whatever it is you're actually trying to build.
If you run into confusion with the API during this process, this is a great place to get help. But if you're not even getting that far because you can't run a Hello World application inside IntelliJ or something, there are probably better sources of help (like forums for IntelliJ, or whatever specific thing you're having trouble with).