Hi, I’m having the same problem. I used to have a free hosting service for my multi-author blog and it got canceled a couple of months ago due to some “slow querries”. I don’t really understand what that means so I moved to a new host with a full backup I had. I also had a plugin that would mail me everyday a database backup, and today I realised that It hasn’t sent me a backup for almost 3 months (about the same time my blog got canceled).
Now I’m trying out your plugin and the same error depicted above happen to me.. maybe this little story helps. Good luck.