I upgraded WordPress at Othermakes.net yesterday and started getting a server error when accessing the WordPress Dashboard. All the regular posts and pages were fine.

To fix this I opened up the file “error_log” in the root directory of the site. You can access that using an FTP client such as FileZilla or maybe the control panel of your host.

You should have some error messages giving you a clue as to what is failing. In my case it was a plugin called postie.

[02-Jan-2012 14:22:59] PHP Fatal error:  Call to undefined function  _fill_user() in /blah/blah/othermakes.net/wp-content/plugins/postie/postie-functions.php on line 2618

To fix this I renamed the /wp-content/plugins/postie file to postie_old.

Now I could care less about postie so in hind sight I should have disabled that plugin and others I don’t use to avoid issues.