I later went into the journal in Control-Access and allowed ALL Journals, just in case leaving it blank had a hiccup. Still have the same problem. In the Outstanding Receipts account I also allowed all journals, I still cannot close and validate (now "close and post") the POS, so I am still stuck in limbo, because I have already closed at the first level, so I cannot go back and resume selling.
So, it turns out that an error I had in my accounting (I did not have accounting as noted previously, so I was able to access journals, but not the chart of accounts) and thus was unable to properly link accounts and journals...something was linked to a journal that was accepted before the update, but is no longer possible after the update. I had to delete said account from the linked journal access.