Error message not informative

Hello,

debugging codeigniter is for me a nightmere. The only error message I receve is 

Fatal error: Uncaught TypeError: Argument 1 passed to CI_Exceptions:how_exception() must be an instance of Exception, instance of Error given, called in /var/www/clubsharing/production/system/core/Common.php on line 658 and defined in /var/www/clubsharing/production/system/core/Exceptions.php:190 Stack trace: #0 /var/www/clubsharing/production/system/core/Common.php(658): CI_Exceptions->show_exception(Object(Error)) #1 [internal function]: _exception_handler(Object(Error)) #2 {main} thrown in /var/www/clubsharing/production/system/core/Exceptions.php on line 190

I cannotunderstand what line produces the error, and so on..

This is the "line". Upgrade to CI3.