Just hit this bug today.
I solved it, together with other related bugs (HTTP 5xx errors, OpenVPN no longer working, etc.), simply by correcting several directory permissions, e.g. /usr/lib, /usr/sbin, /usr/lib/perl/* and some others I forgot to write down, silly me.
They all were with 700 permissions instead of 755, which prevented Apache, OpenVPN, Perl CGI scripts, etc., which run under “nobody” uid, to access needed files and libraries.
Hope this helps others to avoid reinstallation.
Luca.