I have a mediawiki install that is acting up. Whenever I try to save an article, it goes to a blank screen. All though if I refresh that blank screen, it will go on to work.

I have no idea why it's doing that, but it seems to be that it's a problem with PHP. I guess by default errors don't get logged when using mod_fcgid, because I can't find an error log anywhere. I tried enabling logging in the /etc/php5/cgi/php.ini, but that didn't do anything. How do I achieve php error logging? I'm using ubuntu 9.10.