I just struggled for a couple of hours after a White Screen of Death from the admin site of wordpress on my OpenBSD box.
I thought I'd let the forum know what happened, just in case anyone else runs in to this.
Problem: White screen after attempt to login to admin site
Cause: The machine has moved around in the network and now uses a different nameserver.
Solution: I had to update /var/www/etc/resolv.conf to point to the correct nameserver.
How come? OpenBSD uses a chrooted Apache by default. This means that web applications can't access the default /etc/resolv.conf to figure out what nameserver to connect to, so this file has to be copied to /var/www/etc/resolv.conf. I forgot to repeat this after the nameserver change.
Upon accessing the admin site, wordpress attempts to access several remote locations to look for updates, through a PHP fopen(<url>,..) command. When the contents of /var/www/etc/resolv.conf are out of date, this will hang on the name lookup (which I consider to be a bug by the way. It should time out within a reasonable period, within the maximum execution time of the script anyway). Consequence: white screen, no errors in log, no activity on server, nada, nothing!