Demon's Souls not booting

I got the game booting, but had to change the PS3_DISC.sfb.txt to PS3_DISC.sfb by deleting the file extension txt.
Now it works, but the graphics are funky and I can't see the player character or enemies and the game froze when it tryes to load the second tutorial area,if someone has a clue if there is a fix.


Thanks