First we need to get clear that the CCK is for connecting your D* network to the outside world and nothing more. MRV works just fine without any CCK in line. So, I don't think your CCK is part of your MRV issue. When you have a CCK you get addressing from your router, but that is all. The router does not manage MRV (in a standard installation).
Since you have a CCK in the line your receivers will get their addressing from your router. So you should always reset/reboot the router first whenever you are resetting things. Then you can unplug all receivers and then plug them back in at about 30 second intervals. This is the "surest" way to reset your system. With most routers the base address is 192,168.1.1 and all addresses have 192.168.x.x addresses. If you don't see that on your receivers in the internet connection then that receiver is not seeing your router. (However, the receivers seem capable of searching for any unit with a "DIREC.." name and setting itself to use that IP address for MRV. I say that because it seems to be the protocol, but my MRV goes out from time to time and I have to reset the offending receiver when it happens.)
If resetting your receivers fails you have an issue with your settings. I suspect it is a settings issue, but I would do one more reset before I went diving into settings.
Oh yes, one more assumption that I am making is that there have not been any changes in equipment or splitters since you had a professional install. If so, we need to know of any equipment changes that were made to narrow down the possibilities.
(Someone else had your exact same problem a few weeks ago, but I cannot find their post to see what the solution was.)