It worked. I did the change via phpMyAdmin.
The SQL query for the same is:
Code:
UPDATE `pligg_categories` SET `category__auto_id` = '0' WHERE `pligg_categories`.`category__auto_id` =5 LIMIT 1 ;
In the above code, replace 'pligg_categories' with the name of categories table as appropriate. Usually it will be just 'categories' or 'pligg_categories'.