go to the stw directory.
then run all the event anims and cut sceens excetera. (in windows media player)
see if one fails.
Ace megacodeck pack seems to work with STW. so you should be ok with those.

corrupt Poems in the voices folder can also cause similar symptoms.
You can delete poems or replace them with a similar sized poem, that you renamed.

but like i said.
Thats already writen in the STW probs? Read here 1st thread.