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.
Short answer is no, you don't NEED to seal the grout. Grout sealer is one of those products that manufacturers try to sell people that really aren't the best idea in the world. The pitch is that it will prevent mold forming. Well, that is only true in the very short term.