I just noticed that the in POTW Grad students forum one has the ability to post new thread, both in general on the topmost corner of the forum page and in the forum tools. I have snipped a few screen shots
Yes, the admins have recently changed the POTW forums so that people who have submitted solutions can review them there and make attachments to their submissions. In order to do this, posting permission had to be granted. However, all threads posted there are subject to moderator approval, and anyone posting anything there directly, other than a moderator or admin will be issued a 10 point infraction.
As far as I know the POTW forums, where the problems are posted, have always been technically open to new threads being posted by anyone, but so far no one other than Chris L T521 and Jameson have posted there.
Are the High School and University POTW forums not open to new threads by you?