I have hit a snag that I cannot seem to get around. ***SPOILER***
Spoiler
After returning from Durlag's Tower with Hurgan's Granda's dagger, I was set upon by the cult. Kicked their butts at village gate, outside Shan's house and just inside it. The fight in the basement also wasn't too bad as I had thought out a fairly good strategy (correctly figuring in advance that the demon would be summoned regardless). After the fight and killing the blasted thing, which the comments section acknowledged, I did not receive any experience points. I thought perhaps I might get them when I let Huran know I had done it. Wrong Answer! He tells me to hurry before the cult summons the demon !?!
My strategy, though different, was not too unlike others I have read in both places. I saw that the result I have experienced will happen if a certain conversation which triggers the basement encounter is not done. However, I did trigger that conversation, so I am clueless. I have reloaded from a save and refought it three times.
Here is how I did the encounter, if anyone has an idea as to what might be the problem I would be grateful. ***SPOILER***
Spoiler
After cleaning out the main floor I had Imoen hide in shadows and go downstairs to scout it out. Went around the room and noted the cultists and the leader were all "hostile". Went back up and buffed the party. Imoen put a 3 potions of fiery burning in a quick slot, and Coran put 2 potions of explosions in a quick slot. Both of them knocked arrows of biting at the ready in their bows, as did Minsc. Imoen and Coran then went into shadow and snuck downstairs. I put one in each of the near corners. The four upstairs further buffed with potions of mirroring and various strength potions Branwen cast Def. Harm. Imoen and Coran each pitch a potion to a spot behind the leader and become immediately visable. This immediately (before the potions hit) triggers a conversation with the leader and also summons the demon. I answer and then booooom, the potions explode. It only took one arrow of biting to finish the leader. They both step back and drink a potion of invisibility. The rest upstairs come down, I have my PC (elven fighter/mage) go after the first cultist on the right and Minsc switches to his +3 two-handed sword and goes for the one on the left. Coran and Imoen now start pumping Arrows of Biting into the demon (they worked on the Demonknoight so I figured they'd work here). Dynaheir pitches some fireballs to back of the room. After Minsc & I mop up the cultists (Dynaheir really clocked the ones in the back) we start to the demon. Dynaheir and I each use a wand of frost on him and then he died. I need to add that at some point in the fight some or all of my party was frozen by paralyze. Thankfully, none got changed into ghasts. Also I noticed the demon never left his summoning spot and for a brief time did not even twitch (like he was affected by his own paralyze!), could that be from the poison? Perhaps the poison finished him off and the game was not set up for that?
But in the end I succeeded and Huran acknowledged my success.