I tried a few old PVA's yesterday just by chance (ones that had app making disallowed) and they can now make apps. Some of these were the newer ones that had 3 dummy apps that I had used up. The only reason I can think of them now working is that a time limit has passed or on a few of them I had been testing new app installs as they werent any good for making them themselves. So maybe FB them being used and lifted the block. I hadnt used them for anything else..they didnt have any friends. Check your old ones !!