Comment 2 for bug 989788

Hi James, thanks for taking the time to file this bug report and help us make Ubuntu better.

It appears that Nagios was just a victim of insufficient dependencies:

Setting up libperl5.14 (5.14.2-6ubuntu2) ...
Setting up libperl-dev (5.14.2-6ubuntu2) ...
Setting up update-inetd (4.41) ...
Setting up iputils-ping (3:20101006-1ubuntu1) ...
Setting up nagios-plugins-basic (1.4.15-5ubuntu3) ...
perl: error while loading shared libraries: libperl.so.5.12: cannot open shared object file: No such file or directory
dpkg: error processing nagios-plugins-basic (--configure):
 subprocess installed post-installation script returned error exit status 127

As you see, libperl was updated without updating perl, so the linking failed. Nagios uses 'ucf', which is a perl program, and depends on debhelper, which then depends on perl. The problem is that perl was basically in an inconsistent state at that point. It seems to me that perl should Depend: libperl5 ${binary:Version} so that apt will upgrade perl before trying to use perl. Perl is so fundamental to package management though, its possible that this is one of those corner cases that has to be dealt with differently.

Anyway, I believe this is perl's problem, not nagios's, and so I'm redirecting the bug, and marking it as Medium importance.