Upgrade 2.1.1 to 2.4.8 - A database error has occurred

[ctgraham]

When you see a blank page, check your server’s error log for the cause:

When I click some button or follow some link, I'm left with a blank page. What do I do?

Check your webserver error log Usually, this indicates that a PHP error has occurred and the message has been sent to your web server or system log file. Check there – e.g. /var/log/apache/error.log, although the exact location will depend on your server configuration – for further details. Check your file permissions If you haven’t installed OJS yet, then the most likely cause is a problem with file permissions in your cache/ or cache/t_compile directories. See docs/README for information on…