The production overruns were pretty much unavoidable. First Paramount wants a series and spends a boatload of money on it. Then they switch gears and want a feature film. All the production costs (and other things) spent on the series is wasted money because it's unsuitable for a feature film so they have to start again almost from scratch.
But the real failure is not having a finished script before going ahead with anything else. That was begging for trouble.