MySQL_class: Database Error occured!

 CODE: 1064
 DESC: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1
 FILE: index.php
QUERY: select * from categories where deleted='N' and cat_id=
 QCNT: 7
 INFO: Query('select * from categories where deleted='N' and cat_id=') failed!

Please inform exportunity.net about this problem.
PHP v5.4.45 / MySQL Class v0.36