The group I DM for, "The Liberators," finished "Zenith Trajectory," and I must say they took out Dhorlot with nary a worry.
Some of it was a fluke - they all made their will saves for the fear aura (which I wasn't all that surprised to see, as everyone in the group is either a spellcaster or has multiclassed into spellcasting, ergo great Will saves), but the rest of it really was the room.
Dhorlot flees if he gets below 60hp eh? Well, since the group kicked the crap out of him and he ended up at merely 20-odd, it wasn't much of a plan. He didn't manage to survive long enough to try (and the attacks of opportunity from Gaspar, the fighter/cleric with the spiked chain in a room that size was just incredible).
Callis, the druid, basically summoned a small horde of animals to keep the dragon busy (or at least, surrounded and hemmed in); Gaspar the fighter/cleric of Pelor just used his spiked chain and five foot steps to dance around the edge of Dhorlot's reach, Jayna the Rogue/Diviner was pelting off perfect hits with her true strike-sonic-weapon enspelled bow; Draken, the Wizard/Incantatar rolled quite well against the spell resistance issue; and Ev the Ranger/Beloved of Valerian took the opportunity to really show off what a magic composite shortbow and a quiver full of flame arrow arrows can do.
So, now the druid is wearing dragoncrafted red dragon hide armor, and a dragoncrafted black dragon mantle. I can't wait for the half-dragon progeny to show up and be somewhat miffed that the druid is wearing his father, nor for Hookface, who will likely be upset at Callis' wearing of his son. Heh.