Ok, on the PTZ card, the lights should only flash when you submit a PTZ command. If theyre flashing, your COM port should be fine.
I ran into this issue with one ptz on a large install that had 8 other PTZs.
I verified the address by powering the PTZ off and then back on so I could get the address from the camera itself when it did its boot routine and displayed all the info on the screen. The address was showing 0. I tried changing the address on the dip switches, and it was still showing 0 as far as the camera was concerned. I called the manufacturer and he said I somehow got the dome in SOFTID mode...and basically what that is, it is when you use an actual keyboard, not the DVR with the PTZ, the keyboard assigns the PTZ an address on its own. The only way you can get it out of this mode is with a PTZ keyboard from the manufacturer of the PTZ. My dome was a Veilux. I had no PTZ keyboard and was not going to pop a few hundred on one, so I sent it to the manufacturer and had them take it out of that mode.
So try changing around the address on the actual ptz dip switches, and see if when you power the camera back on, the address it displays is what you put on the dip switches.
Another possibility is you have it wired wrong.
And one other possibility is if you have another PTZ on the system, you could possibly have it interfearing.
I once sent a contractor out to one of my clients to replace a PTZ, and the idiot shorted something in the PTZ, and that caused 3 out of 10 to act weird. 2 would not respond to PTZ control, the 3rd did whatever it pleased.