Joomla 1.5.20 acesef 1.3.11 doesnt work

htaccess is ok,
acesef is enabled but not effective ...
Global configuration is ok

when i click on "extensions" i have :
Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /homepages/44/d225854831/htdocs/photos/libraries/joomla/database/database/mysql.php on line 344

Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /homepages/44/d225854831/htdocs/photos/libraries/joomla/database/database/mysql.php on line 344

Warning: Invalid argument supplied for foreach() in /homepages/44/d225854831/htdocs/photos/administrator/components/com_acesef/views/extensions/view.html.php on line 63

and when i click on SEF URLs :
Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /homepages/44/d225854831/htdocs/photos/libraries/joomla/database/database/mysql.php on line 344

Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /homepages/44/d225854831/htdocs/photos/libraries/joomla/database/database/mysql.php on line 344

idem for meta manager and moved urls...

Any ideas ?

PHP 5.2.13
joomla 1.5.20
acesef 1.3.11