I'm experiencing the same issue. I have the most recent version of Java (6, Update 32) and I've republished my course in Presenter and I still receive an LMS API error message. We have a license on a couple of computers and I'm receiving the error on the other computer as well. Any thoughts?
Grout needs between 48 and 72 hours to dry before it can be properly sealed. Despite the fact that grout often looks dry within a few hours, sealing it too early can damage the grout and keep it from effectively doing its job. Keep Learning.
All you need to do is leave the grout to dry before getting it wet. The instructions should tell you for how long. As you and others have pointed out drying and curing are separate things. While you can use the shower after the grout is dried you may need to leave it for a day or two after it's cured before sealing.