Getting following web services error after activating the Rewards Plugin

Question

When activate "sumo reward points" plugin and run this

http://imexleader.com/webservice/login.php?action=login&username=sanjay&password=san123" webservice. 

It gives me following errors:

Warning: call_user_func() expects parameter 1 to be a valid callback, function 's.t.r.r.e.v' not found or invalid function name in /home/imex323/public_html/wp-content/plugins/rewardsystem/inc/class_reward_system_menus.php on line 214

Warning: call_user_func() expects parameter 1 to be a valid callback, function 's.t.r.r.e.v' not found or invalid function name in /home/imex323/public_html/wp-content/plugins/rewardsystem/inc/class_reward_system_menus.php on line 215

Warning: call_user_func() expects parameter 1 to be a valid callback, function 's.t.r.r.e.v' not found or invalid function name in /home/imex323/public_html/wp-content/plugins/rewardsystem/inc/class_reward_system_menus.php on line 220

Warning: call_user_func() expects parameter 1 to be a valid callback, no array or string given in /home/imex323/public_html/wp-content/plugins/rewardsystem/inc/class_reward_system_menus.php on line 221

Warning: call_user_func() expects parameter 1 to be a valid callback, function 's.t.r.r.e.v' not found or invalid function name in /home/imex323/public_html/wp-content/plugins/rewardsystem/inc/class_reward_system_menus.php on line 222

Answer 1

You have a hacked version of the plugin! Check your plugin or delete.

strrev is is php function for reversing a string, it is commonly used in hacking schemes.

http://php.net/manual/en/function.strrev.php