I really don't think Kenzer's having problems. I could be wrong, but I just don't think they are.
I would assume that periodicals just don't sell as well for the store to continue selling them. Often retail stores have to get a certain amount of a magazine to maintain their discount. If they aren't selling enough to warrant buying them, the store may have stopped. Ask the manager if anyone else has asked about it. It seems strange to me that a game store would have trouble selling copies of Dragon, Dungeon, KODT and such but you never know; esp if people get it delivered to their home.