Playing a bit more, when enabling Error Reporting to Maximum and reloading the course page for the user listed above, I see this error -
Notice: Undefined index: seo in /homepages/19/d345309865/htdocs/textile2015/components/com_guru/router.php on line 605
There are also some "Deprecated Function" messages relating to Gantry. Changing the template away from what the Cloudbase3 template TextileEvolutionStyle to Beez3 resolved the problem of linking to sections of the class that the user has signed up for, but the com+guru/router.php error listed above still appears.
When logging in as my own superuser, I get the same error messages but the pop-up windows for the course lessons work as expected.
Adding superuser capability to the anjamartens36 user listed above resolved the problem with accessing the additional lessons.
Looking at lessons for the Fabric Embellishment class, I see that "Who can access this lesson" is set to "Members". I don't see this as a group that she can belong to - is this something you can explain to me or help me resolve?