Cablemonkey

I volunteer at my local Emergency Management Agency, and installed there camera system they use in there new building, it is a 16 camera DVR, I have 4 monitors on it right now for the Director, Asst Director, Operations officer, and the Drivers license center, they are wanting 2 more put in, one for the Highway Patrol office, and the reseptionist. Here is what i am running into ( i dont have the DVR model number in front of me at the moment ) I have tried just a 6-way splitter and nothing, i also put an amp in before the splitter to see if it would deal with signal lose, but it didnt work eather, i cant even get the 6-way splitter to run the original 4 monitors i have to use the old splitter. What am i missing. Any help would be great ( I will get some numbers off the amp and splitter and post them when i get them in front of me, but off the top of my head the splitter is 5-1000Mgz at -11db, i think that sound right? )

Here is how it is run. Out of the BNC video out of the DVR, all the cable is RG6 (the closest of the 4 monitors that are working now is at least 40' from the soarse) run into a splitter/combiner, then out to the Video 1 of the "monitors" which i should have mentioned are just flat panel TV's.