[Lynne]

Disable your plugins and see if the error goes away.
Note: To temporarily disable the plugin system, edit config.php and add this line right under <?php

PHP Code:

define('DISABLE_HOOKS', true); 


If you want to know what all the mysql terms mean, then you should go take a look at the mysql site. Do a search of "mysql term" - example:
"mysql limit" - http://php.about.com/od/mysqlcommands/g/Limit_sql.htm
"mysql null" - http://dev.mysql.com/doc/refman/5.0/...with-null.html

etc.