The version number is the version of the map compiler. It may be 6.31, but SED has 1.2.8 and MED has something else along with WED.

When about to run the level, you'll see an input field. Type a space at the very end then "-diag" without the quotes then okay it. This creates the engine log, of which JCL is asking for.

Just in case, be sure you don't have any exit(); instruction somewhere in your code.