You might encounter the error message "500 Internal Server Error" for web scripts such as asp, php, cgi or Server Application "/" Error for asp.net application.
In order to ease of troubleshooting these errors, you might want to disable �Friendly HTTP Error Message� of your Internet Explorer.
Go to Tools > Internet Options > Advance tab and uncheck the option "Show Friendly HTTP Error Messages". Refresh your browser again and you will get the actual error message.