Really need to see the rest of the publishing settings. For example, if you are using ‘seamless play’, I would uncheck that and republish to see if that clears up the issue. You may try this with other settings as well to isolate the potential problem.
Also, have you tested in other browsers besides Chrome to see if you get the same error? (troubleshooting to see if you are taking about an issue that can be resolved from the browser side, the Lectora publishing side, or LMS).