I was wondering though, do you just happen to get this error today? How long does it persist? It appears that your site has too many concurrent mysql connections at the same time, usually this shouldnt be a problem as the connections are automatically closed after a while. Try again later and see if this problem still wont go away. In this case, you may have to define some mysql settings as specified here:
http://dev.mysql.com/doc/refman/5.0/...resources.html
Another way is to contact your host and kill all processes on your site so all those connections are gone. It will make your site work for now, but not sure if it will come back some time later. There's a chance that your server aint getting rid of old connections properly.