I can only guess: you probably were muted for announcing it too often. This would be spam. Yes, in medieval times people would do that, but given the textual system we have to work with, this method cannot be simply copied 1:1. Instead, other means must be provided, like auction houses (special, closed areas that confince all biding, only those in the area will see it) and ebay-like ingame auctions (in order to compensate for RL time constraints).
Anyway, I think the ROTP issue is more or less completely OOC anyway, since the item itself is completely OOC (and thus shouldn\'t even exist, even if I had one). Yet, I haven\'t seen such an auction myself yet, so I think it is more or less an infrequent thing. What I see, however, is a player driven market for weapons. There are even two stores that I know of: The Hydlaa Outfitters (in Hydlaa) and The Community Of Vaalnor Shop (in Ojaveda). Both seem perfectly IC and perfectly desirable AFAICS, and they work without the highly questionable auction channel.