How to properly add JavaScript to drupal
If your code sample is accurate, and you are calling drupal_add_js() from outside a function in a module file, then that will be the problem.

You would want to add your js from within your hook_block_view().
This way it loads after drupal has done all it needs to do with its js and jQuery will exist.

Also, you might not want to put your map initialisation in a behavior, because you would usually only ever want your map to load once, on page load.
I don't know all the details of your setup though so I can't know exactly what is best in your case.