I am not sure if the SpringWare boards (D/... family) and the DM3 boards (DMV... family) were ever meant to work together. It would be best to pose your query to Dialogic's technical support (
http://www.dialogic.com/support/).
I know that if you have more than one Dialogic board in your system, you have to either disable the CT Bus clock, or synchronize the clocks between the two cards - and also connect the ribbon cable across the top.
In any event, TeleFlow does not support the DM3 family of boards, so you will not be able to use your DMV600AWE1 with our software. My recommendation would be to remove the DMV board, and run with just the D/300. That should be a simple configuration so you can verify that the rest of your application will work. Once you've got that far, you can try adding in a 2nd D/? card.
Also, check out this wiki topic for advice on installing Dialogic hardware/software for use with TeleFlow:
http://www.teleflow.org/wiki/index.php5?title=Install_Dialogic.