My apologies for the recent sever outages... this was caused by 2 things: I ran out of disk space (oooops, that was careless), I believe the knock-on effect from that caused MySQL to get all upset so it wouldn't run.
I've since freed up well over 11GB of disk space, so that should see us for another couple of years (I forgot I had a complete backup of MEM on disk.... yes, that's the space this forum takes up now, 11GB!), after which I'll need to upgrade the server again.
I've also increased the maximum number of simultaneous connections allowed to the database, so hopefully we won't see that message for a while either. I'll keep an eye on it, and if it looks like I need to increase it again, I will do so.
Meantime - apologies again for the outages. Hopefully it won't happen again anytime soon!