If you don't tell us the exact error messages you get, we can't tell you what's wrong, and it's also useful to know exactly what command you're typing where appropriate.
If it's a Java programming error:
a. is it a compile time error? Paste the exact compiler error
b. is it a runtime error? Paste the full exception stack trace if there's an exception. For Exception 'e', that would be obtained with e.printStackTrace();