Upgrading to Nvidia driver ver 191.07 released 10-5-09 fixed the problem below for me. Running XP Pro on a Dual Core Quad Intel and a Nvidia 8500 GT card. It did not fix the church bug, same as it ever was.
After playing the sewers under the merchant area the game suddenly stopped following my character. I could move the pointer to the edge of the screen in any direction and the screen would move but would not move as my character moved. Tried re-starting and re-saving. I used the ladder to return to the merchant area, the sound effects were correct but my character stayed in the sewer. Tried to use the Teleporter Stone, my character vanished but the screen remained in the sewer. I reloaded and continued to play using the pointer to change screens. I was hoping to finish the level not realizing how big it was.
Finding a stairway in the northern part of the sewer, I clicked on it which caused a crash similar to the church. I re-loaded and continued to play using the pointer to move from screen to screen. I found a sewer cover in the southern part of the sewer and clicking on it caused the same crash as the stairway . . .black screen and exit dialog.
I also crashed when a lizard hit me with a fireball. I found by side stepping the fireball that I could clear the room without a crash. (Have not found a fireball lizard since driver install) It was very similar to the church bug when the monk is hit with a fireball. I continued until it was just too much trouble to play.
Checked Nvidia web site for new release drivers and found the driver ver above which cured all of these DD problems on my system . Again, it did not fix the church bug.
Edit: Also, with the above problems, the S and L keys stopped working. Could only save or load using the Esc key. This was also fixed with the video driver update. Go configure??

So that's the only problem left, right? Which resolution are you playing with?

The church bug was NOT fixed and it seems to be the only bug I have now. Using 1280 x 1024 res.
Been playing for 2 - 3 hours since I updated the driver, much improved, finished sewer with zero problems. I have noticed that the clicks work better now as well, was taking several clicks to pick an item up or open a door, now works with one click.
Tried the church first thing and got an immediate crash. I have had few problems except the church and sewer. Driver helped some small problems (clicks,colors) I had not noticed as well. Great game !

This can be because CapsLock was on. You can look around the area holding SHIFT: your character will stay put and you can move the camera.
So anyone having the "camera doesn't follow my character", check if you can solve this be pressing CapsLock or shift.

Thanks for the input, putting the CapLocks on does cause the same affect. I did push the Shift key and CapLock keys when this occurred, several times during and after reloading, but got no change, sorta like it was hung up in this mode, even when I reloaded the game. It was right after the initial battle and started when I tried to leave the entry room and move to the main sewers.
The S key and L key also did not work as expected. I pushed the Caplock ,Shiit key, S key and L key many times, thought maybe the shift key was stuck . . . tested all keys and Caplock in Word and found them to be OK . . .except in DD. Esc did work for saving an loading. Restarting the game several times had no affect on the issue.
Along with the screen and key issues, I couldn't leave the sewer . . . by any means. Basically, I could not go any further and would lose all progress I had made in the game. It was at that point I looked for new driver releases.
Tried playing one more time before updating the driver with no change. Updated the driver and all issues above were gone, I could leave the sewer by all methods, the screen worked as it should and all keys did what they were supposed to do. Played for 2 or 3 hours after with no problems.
Still can't enter the church or use statues, both cause a black screen and error dialog. Other than that (so far), the game is playing great, I will play again this weekend and post any other issues on this thread.
Edit: Maybe new driver writes to a different memory address avoiding some or most corruption during game play ??? The game does play better with the new driver and none of the issues above have occurred again.