check course content

shouldn't need anything outside of drupal core to do this

$group = og_get_group_context() will always supply the group that's in context (elms site)

If you want a specific content type being accessed, you can do the following

$node = menu_get_object();
if (isset($node->type) && $node->type == 'page or whatever type you want here') {
  //do something
}

Elms Content defines the page, link and folder types. ELMS site defines site and ELMS parent defines parent (just a high level organizer).

As much as possible ELMS seeks to simply implement conventions established by OG and Spaces when it comes to data management and organization.

Did you make sure it's been told that it's allowed to be posted in groups? It need to have the setting of group content selected.

Do you have a menu item link within a group that has a path that makes sense to the group. For example mysite.com/node/add/type, even when accessed within a group will NOT associate it to the group. Make a menu link that you have access to within groups (like a menu that's in a block or navigation and place that in the left region via context). Then make sure the link has

Persistant URL behavior
All links are normally rewritten to contain the active persistant url elements. You may set this item to maintain existing modifications (the default), or to discard them.
BEHAVIOR: MAINTAIN

If you don't maintain the PURL setting for the link it won't modify node/add/type to {currentgroup}/node/add/type and then won't be able to populate the group setting automatically.

og_get_group_context() is your friend at all times :)