QT CBR Mpeg encoder not constant?

AFAIK you won't be able to create the type of MPEG stream required by the server using Compressor. For DVD-Video purposes a CBR encoded MPEG file uses a more or less constant bit rate, as long as that bit rate is really required to encode the video. In easy to compress sections of the video (e.g. a still or near motionless video) the bit rate will drop below the bit rate set.

You will probably need an MPEG encoder that can create "transport streams" and which pads those low bit rate sections to keep the bit rate artificially constant.