Does solid, continuous ceiling insulation without vents affect house in any negative way? If you fill exterior rafters with solid insulation, is there a problem?
Maybe, maybe not.
Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed. --Herman Melville
The reason why Dan's post - though annoying - is absolutely spot on is that you are not givin us enough information.
If all you are doing is stuffing the bays full of insulation, without any regard to air sealing or roof integrity... well, don't be surprised if you are surprised by you home rotting.
The reason a roof is ventalated is to remove the vapors that rise out of a house, before they collect and condense onto the underside of a cold roof deck. If you take GREAT care in air/vapor sealing and removing extra humidity sources, maybe even an ERV, you could go with fully filled rafter bays.
Usually filled bays involve some sort of spray foam, as it seals out air and prevents condensation against the roof deck.