Problems with DV editing

I am using a Cinewave system and I am editing DV material captured via firewire.
The editing is all fine but I am getting very erratic results on the external monitor. Sometimes it doesn't display at all and sometimes when you play the edit it just gives you a freeze frame on the monitor, hence I get the same problem when editing to tape via the breakout box.
I have read a few reports that the Cinewave setup doesn't like the DV codec, could somebody confirm that this is the problem and possibly suggest a way round it as we are going to be using DV more and more now.
My only thought it partitioning the Hard disk and having the Cinewave/FCP setup on one partition and a clean FCP on another partition for DV editing only....is this a possibility and how to do it.
Any thoughts would be greatly appreciated.

Paul