The resistor that was removed as far as I know is only relative to PSX games, and shouldn’t have anything to do with DVD playback.
As for your screen rolling, this sounds more like a PAL/NTSC issue then anything. What region is your PS2 and what region is the DVD you are trying to play back. Also the green screen will happen for the same reason. The version of DMS3 you have is supposed to disable the green screen.
Also as long as everything else is working, i.e. PSX back-ups and PS2 back-ups, I wouldn’t worry about the DVD play back. The PS2 is a crappy DVD player to begin with, not to mention that playing DVD's puts undo stress on the laser making the crappy laser you have in your V4 already just go kaput that much faster.
However patching the cut track shouldn’t be that big a deal for your installer, and I'm sure if you contact Rich at
www.richspsxparts.com he can set you up with the missing part. If not him for sure contact Shadowknight since he is an aussy, I'm sure if he doesn’t have one that he would know some one down under that would.
But seriously think about getting a stand alone DVD player and not worry about it as long as your game back-ups are working correctly.