Regression Issues

Ugh, a 4-hour eLearning course is brutal enough, having to complete it in one sitting would be borderline-sadistic.

One train of thought is that the connection to the LMS may be timing out. You could keep it "alive" by sending a regular "ping" to the LMS from within Storyline using JavaScript. If you have the course broken into scenes, on the last slide of each scene, insert this JavaScript in a new Trigger (after creating a new Storyline text variable titled lmsStatus):

var player = GetPlayer();

function findLMSAPI(win) {
     if (win.hasOwnProperty("GetStudentID")) return win;
     else if (win.parent == win) return null;
     else return findLMSAPI(win.parent);
}
var lmsAPI = findLMSAPI(this);

var lmsStatus = lmsAPI.GetStatus();
player.SetVar("lmsStatus", lmsStatus);
lmsAPI.SetStatus(lmsStatus);

A Multi-SCO packager allows you to take individual modules which have been published and ZIPped as SCORM and combine them into a single deliverable. You can then either force the learner to go though the modules in sequence, or allow them to go through the modules in whatever order they wish (similar to an LMS where multiple SCOs are delivered in a curriculum; the learner is either required to go through them in sequence or in any order).

Adobe Captivate includes a Multi-SCO Packager. I've also seen one from JCA Solutions (now part of Rustici) called Simple SCORM Packager. Both are development tool-neutral, which makes it easy to combine SCOs which were created in different tools. As long as they're all the same version of SCORM, and have a standard manifest file, you can create a Multi-SCO course.