[andrewas]

1). WhoWhatWhereWhenHow? Must have missed that plot.

2) Possibly your WIS score is too low, you need 10+spell level to be able to cast.

3) Target it on the ground, not on yourself or an enemy.

4) Stores in NWN generaly suck compared to what you can find just lying around. Use your cash for scrolls, potions and other consumable, but don't expect to find a new weapon there very often.