eternal darkness gamebreaking bug

I've encountered a bug in the rom for Eternal Darkness. During the interlude before Chapter 6 the player is supposed to be able to approach a dresser on the second floor, use the "reveal invisible" spell with the blue rune to reveal a keyhole. The dresser key must be used to unlock it so Alex can access a gun & the next page so that the next chapter can be played.
For some reason, after using the "reveal invisible" spell, I still get the cutscene showing the lock being revealed, but any attempt to actually use the dresser key results in failure. I've tried going back in my saves to see if somehow I missed something, but at this point I'm pretty sure it's a bug that's hard wired into this rom itself. There's no way to start Chapter 6, so this has completely killed my run. Has anyone else encountered this and (oh please oh please) know of a fix?