Help...

[Elfshawol]

I'm currently in the nave, working on collecting the ingredients for Agrippa's tonic and the pieces of the orb. I have all three ingredients, and I had four pieces of orb... but I think I messed something up. In the choir, I had gotten the piece of orb in the brass bull room, but then died trying to get out. (oops.) After that, it wasn't in my inventory, and when I went back to grab it again, it wasn't there. So, now I only have 4, instead of 5. I don't know what to do about that. Also, I tried putting the pieces I had together when I was in the chancel... obviously it didn't work because I only had 4 pieces, but according to a walkthrough, I should have been ambushed by gatherers right when I walked in. I'm so confused. Help from anyone who's played through the game would be greatly appreciated...^^