If you see an error message like below:

This likely indicates you do not yet have permission to view a Lecturecast video.
To gain permissions, you need to click a Lecturecast activity link to access the relevant Lecturecast section for your module. Your tutor or course administrator, should provide you with this link on each Moodle course that has a corresponding Lecturecast section, but if not please ask them to do so.
The Lecturecast activity link will appear alongside the Lecturecast icon on Moodle, and should display similar to the image below:

Click the activity link, and load the subsequent page. The page should display the name and module code for the Lecturecast section you now have permissions to view. You should now have permissions to view any linked videos associated with the module.
For example:
In the Moodle course ECON0001, you must click the Lecturecast activity link to open the ECON0001 Lecturecast section. You can now return to any linked videos and watch ECON0001 Lecturecast videos without needing to follow the activity link again.