Or some time of "database timeout" error?General Error
SQL ERROR [ mysql4 ]
User ?????_phpb1 already has more than 'max_user_connections' active connections 
An sql error occurred while fetching this page. Please contact an administrator if this problem persists.
It seems that there are too many user connections on the database, which cause an overload. I googled for a solution but none of them worked or doesn't applied to my PhpMyAdmin panel or SQL version. I guess I will contact my webhost about it to see if they can increase the maximum user connections.
If you see this error sometimes when you try to post, how often does it occur? And how long does it usually last?