So I bet your problem what we have been saying all along here. It is the only explanation even know you seem to not beleive us and even tried to open a second ticket on this.
You say you have one database but that cant be with the problem you report. Let me guess you had one database but if thats so then maybe you had two sets of database tables with different prefix's and you where using the wrong one for the forum block
You can respond back and let us know which one it was two databases or two sets of tables.