There is a problem with the current version of mediaWiki we are using on this site. We think it is causing all the spurious warning message being posted as you navigate from page to page. It seems to be out of sync with recent underlying software updates to the PHP handler that is maintained by our web provider service company. We are working on the fix and we are very sorry for the distraction.
We have gone through one series of upgrades, and have another, more complicated set still to do. We are working to finish this work.