In that case the idea was not flawed "at the technical level", but at the personal level. Like I say in another comment, a good engineer never blames her tools- especially so when PEBKAC, yes?

To make yet another analogy, I know almost no C++. If you asked me to write some C++ templates to configure your system, I'd probably make a very big mess. Despite the people saying that they're a bit like unification and so on. I just don't know how to use them. So don't ask me to. And don't ask your users who don't know Prolog to use it. That's a bad project management decision.

Also, friendly advice: configuration predicates in Prolog should _never_ _ever_ _ever_ be "rules"; only "facts". That way you don't risk infinite recursions- or run much risk besides. The same goes for any other language I think: don't let the configuration execute arbitrary code or you're in for a surprise, inevitably.