The server it's intended to run on is Debian Squeeze 32 bit (running as an OpenVZ guest). But it also does the same thing on Linux Mint 12 (32 bit). In both cases I've used the 2.12 .deb package (one via apt-get, the other by downloading the file directly).
I've loaded it both via the supplied init.d script and by running it directly as root. Mostly been running as root on the Debian VM and letting the script load it on Mint.
Last night I actually managed to work around it. It seems that the failed rule creation will actually save a file anyway, although not with the right settings. Manually editing it worked perfectly, and will probably work fine for my needs anyway :P
Is it worth trying a build from git?