[mschaef]

The first line of the error message tells you where and what the error is, almost exactly:

    ... Don't know how to create ISeq from: clojure.lang.Symbol, compiling:(hello.clj:5:3)

It's true that the full interpretation of the error message requires some experience with the language (ISeq? Symbol?), but when is that not the case? Consider this one character typo in a Java file:

    voidx displayMessage(String message);

javac produces an error message that's just about as opaque as what Clojure produces in your example.

    [ERROR] ... MessageSink.java:[5,4] error: cannot find symbol

Conversely, if I leave an open brace in Java source, I get the following kind of error from javac:

    [ERROR] ... ConsoleMessageSink.java:[12,1] error: reached end of file while parsing

If I leave an open form in Clojure, it at least tells me the location of the form I left open:

    Exception in thread "main" java.lang.RuntimeException: EOF while reading, starting at line 18, compiling:(toto/data.clj:255:1)

(Of course, thanks to paredit-mode, I had to play a minor trick on my editor to get it to let me even introduce that error in the first place.)