Rafael,
I reproduced this problem on dotlrn-1-0 from last night (server is here:
http://dotlrn.collaboraid.net/test) and the problem seems to be that /dotlrn/forums is not mounted in dotlrn-init.tcl.
I'm trying to access the Sloan sources and asking other people for help. I'll let you know when it's fixed.
/Peter