I think you must ask your ISP to help with this.
Maybe they only need to restart Apache (or whatever the webserver is) to fix it.
Thy will probably tell you that they did not change anything! They usually do. It is easiest for them!
Try executing the same query from phpMyAdmin (I think you have it?) on the server!
I would like to see if you get the same error then.
BTW: you should consider upgrading SQLyog! It is a free upgrade to 5.17!
http://webyog.com/sqlyog/upgrade.html