The MySQL daemon/engine on your server has run out of (allowed) space for storing its own database files. If the filename/path mentioned includes "/tmp/" in it, then the ...
This error seems to be common on Windows installations. Open your includes/configure.php and admin/includes/configure.php and change:
define('DIR_FS_SQL_CACHE', '/tmp');
to:
...One of the most commonly encountered errors is a warning that the installation directory exists at /such/and/such/an/address. It is recommended that you delete or rename ...