Error when trying to refresh cache

[11coexist11]

Hello,
I placed all the files in the appropriate folder and then when I refreshed the cache I got the following message:

Warning: include(/home/devnation/public_html/includes/src/Netzarbeiter_NicerImageNames_Model_Observer.php) [function.include]: failed to open stream: No such file or directory in /home/devnation/public_html/includes/src/Varien_Autoload.php on line 93
#0 /home/devnation/public_html/includes/src/Varien_Autoload.php(93): mageCoreErrorHandler(2, 'include(/home/d...', '/home/devnation...', 93, Array)
#1 /home/devnation/public_html/includes/src/Varien_Autoload.php(93): Varien_Autoload::autoload()
#2 [internal function]: Varien_Autoload->autoload('Netzarbeiter_Ni...')
#3 [internal function]: spl_autoload_call('Netzarbeiter_Ni...')
#4 /home/devnation/public_html/includes/src/__default.php(24126): class_exists('Netzarbeiter_Ni...')
#5 /home/devnation/public_html/app/Mage.php(463): Mage_Core_Model_Config->getModelInstance('nicerimagenames...', Array)
#6 /home/devnation/public_html/app/Mage.php(477): Mage::getModel('nicerimagenames...', Array)
#7 /home/devnation/public_html/includes/src/__default.php(21714): Mage::getSingleton('nicerimagenames...')
#8 /home/devnation/public_html/app/Mage.php(448): Mage_Core_Model_App->dispatchEvent('controller_fron...', Array)
#9 /home/devnation/public_html/includes/src/__default.php(17911): Mage::dispatchEvent('controller_fron...', Array)
#10 /home/devnation/public_html/includes/src/__default.php(21147): Mage_Core_Controller_Varien_Front->init()
#11 /home/devnation/public_html/includes/src/__default.php(21492): Mage_Core_Model_App->_initFrontController()
#12 /home/devnation/public_html/includes/src/__default.php(20752): Mage_Core_Model_App->getFrontController()
#13 /home/devnation/public_html/app/Mage.php(684): Mage_Core_Model_App->run(Array)
#14 /home/devnation/public_html/index.php(72): Mage::run('', 'store')
#15 {main}

I am not sure if I missed a step or did something wrong. I did also clear the cache through the FTP but still got the same message. Can you please let me know how to fix this error? Thanks!