I have a similar problem. My compiler was turned on and I did the installation. Now, getting error 500 and log file shows this error
[21-Sep-2016 01:25:37 UTC] PHP Fatal error: Class 'Aschroder_SMTPPro_Model_Mysql4_Setup' not found in /home/strateg2/public_html/picworks.in/includes/src/Mage_Core_Model_Resource_Setup.php on line 234
I'm unable to log in to admin panel. How to resolve this issue.