I may be wrong, but I wouldn't worry too much about that message. I find that in my home setup of phpMyAdmin. I think it's an issue between MySQL and phpMyAdmin, and not exactly with XOOPS. My XOOPS set up runs fine with those phpMyAdmin messages.
Hmmm... come to think of it, I may have ignored that message for far too long.
The Documentation Team is still working on some help documents for download. We've just released a document, "Visual Introduction to XOOPS", which is available in different formats. You can see it at the left column.
I guess, the wiki will do for now. But, rest assured, the team is working on more XOOPS documentation.