For the first question, that line number is what comes back from Oracle and what they're telling you is that the error is occurring on the 42nd line of code that they see. You'll see the same error if you were to run it via SQL*Plus. Once you
execute the script, go to the Messages tab on the Editor and you'll see a tab with Errors. Clicking on these errors will take you to where the line actually error'd out.
I'll have to let someone with ninja level SQL skills answer question #2.