You know, I am getting this same error with the file as I just upgraded from 5.47d to 6.04 on a NT server and the copied the files over to a Unix server. I have doubled checked over and over on the permissions.
I have played around with the board and I can't make a post, reply to a post, update my profile, and do any private messaging. The end result is a white page saying that there is an error.

The only thing that works on my board is search engine.
I won't redirect my members over until I get this corrected of course. But if you any you "UBB Techs" could lending a helping hand, I and probably others would really appreciate it.
Here's the link to my new board:
BHM Discussion Forums Thank you for your time.
Julian