Did you use any group to kill Phinny? If you did, then you can use the same one to kill an Amygdalan Warrior. If you are trying to solo an Amygdalan Warrior by kiting, that is your problem. The agro in PoF is insane with the range. I couldn't solo Phinny (then again, I was only level 47 at the time), so I had a 65 magician, 65 enchanter, and 65 cleric help me. (Since I know them all in RL, it was no problem). We also killed the Amygdalan Warrior with the same characters.
At the beginning, what you need to do is either kill all the spectres, or you need to have Invis vs. Undead on and run through the spectres, then before you zone in, put on a regular Invisibility, then run to the left. I don't have a character on Tarrew Marr, otherwise I'd be willing to help you :( .