Please don't create new topics for rooms if one already exists:
http://forum.caravelgames.com/viewtopic.php?TopicID=19
This may well answer your main question.
Regarding the other: If you return to a room that you thought you had conquered and it has live monsters in it, there are a couple of possibilities:
1) You have restored your game to a point before you conquered the room.
2) You left something alive when you left.
3) Someone is doing something funny with scripting (not an issue in this particular hold).
Josh
____________________________
"
Rings and knots of joy and grief, all interlaced and locking."
--William Buck