5 on an IIS 7 Server and we' re having problems making PHP errors visible. At the moment whenever we have a PHP error the server sends back a 500 error with the message " The. A Guide To PHP Error Messages For Designers]. If you now run the script that caused the error, the error message should get added to the php_ error. SESSION[ ' Error' ] = " You left one or more of the required fields. if( isset( $ _ GET( ' x' ) ) ) { / / your html for error message }. < input type= " submit" value= " Login" > < span>