What were the most recent modifications you did to your forum prior to the issues popping up?
From the errors you posted it seems like you are missing a db table and and in the other error, that column doesn't exist in the table or maybe it is misspelled.
Actually what started it was I was updating another site and put in the PW an Username for another site. So I went back and corrected it - on the updated site - but then these errors started to occur from which I got the wrong PW and username. I tried to run some SQL commands but they didn't do any good.