Slim Application Error

The application could not run because of the following error:

Details

Type: ErrorException
Code: 2
Message: A non-numeric value encountered
File: /var/www/phpdev/lib/Phpdev/Collection/News.php
Line: 42

Trace

#0 /var/www/phpdev/lib/Phpdev/Collection/News.php(42): Slim\Slim::handleErrors()
#1 /var/www/phpdev/controller/tag.php(7): Phpdev\Collection\News->findByTag()
#2 [internal function]: {closure}()
#3 /var/www/phpdev/vendor/slim/slim/Slim/Route.php(468): call_user_func_array()
#4 /var/www/phpdev/vendor/slim/slim/Slim/Slim.php(1357): Slim\Route->dispatch()
#5 /var/www/phpdev/vendor/slim/slim/Slim/Middleware/Flash.php(85): Slim\Slim->call()
#6 /var/www/phpdev/vendor/slim/slim/Slim/Middleware/MethodOverride.php(92): Slim\Middleware\Flash->call()
#7 /var/www/phpdev/vendor/slim/slim/Slim/Middleware/PrettyExceptions.php(67): Slim\Middleware\MethodOverride->call()
#8 /var/www/phpdev/vendor/slim/slim/Slim/Slim.php(1302): Slim\Middleware\PrettyExceptions->call()
#9 /var/www/phpdev/public/index.php(14): Slim\Slim->run()
#10 {main}