Can't access threads

[Alice Portman]

Though I can get into the forum itself, whenever I try to access a thread I get this message: Database Error: Unknown column 'a.file_hash' in 'field list'
File: /home/noeltyl3/public_html/discussion/Sources/Display.php
Line: 711

I have no trouble accessing the threads in other forums so I think something must have gone wrong here.

Alice