Magento 1.9 – Warning: include: failed to open stream: No such file or directory

I get this error in my system log but don't really understand what the problem is:

2017-12-05T14:22:42+00:00 ERR (3): Warning: include(Mage/Points/Block/Adminhtml/Customer/Edit/Tabs/RewardPoints/History/Grid.php): failed to open stream: No such file or directory  in /domains/dev.domain.co.uk/http/lib/Varien/Autoload.php on line 94
2017-12-05T14:22:42+00:00 ERR (3): Warning: include(Mage/Points/Block/Adminhtml/Customer/Edit/Tabs/RewardPoints/History/Grid.php): failed to open stream: No such file or directory  in /domains/dev.domain.co.uk/http/lib/Varien/Autoload.php on line 94
2017-12-05T14:22:42+00:00 ERR (3): Warning: include(): Failed opening 'Mage/Points/Block/Adminhtml/Customer/Edit/Tabs/RewardPoints/History/Grid.php' for inclusion (include_path='/domains/dev.domain.co.uk/http/app/code/local:/domains/dev.domain.co.uk/http/app/code/community:/domains/dev.domain.co.uk/http/app/code/core:/domains/dev.domain.co.uk/http/lib:.:/opt/php/php-5.4/lib/php')  in /domains/dev.domain.co.uk/http/lib/Varien/Autoload.php on line 94

Here is the code from Autoload.php file:

82. public function autoload($class)
83. {
84.    if ($this->_collectClasses) {
85.        $this->_arrLoadedClasses[self::$_scope][] = $class;
86.    }
87.    if ($this->_isIncludePathDefined) {
88.        $classFile =  COMPILER_INCLUDE_PATH . DIRECTORY_SEPARATOR . $class;
89.    } else {
90.        $classFile = str_replace(' ', DIRECTORY_SEPARATOR, ucwords(str_replace('_', ' ', $class)));
91.    }
92.    $classFile.= '.php';
93.    //echo $classFile;die();
94.    return include $classFile;
95. }

Sometime customers do not receive their points for their purchase.

I am using Magento var. 1.9.2.4 and have a extension for "Reward Points" by Magestore Extension

Any ideas?