I was setting a shop when the server froze, after I came back, I couldn't set a shop. It says that I already have a shop set, but I don't. As this is the first time that I try to set a shop, I guess he is the one I'm supposed to speak to for the shop closure, ain't he?
When this happens, you need to wait 24 hours and then speak to Fredrick again, and you will be able to reclaim your items and set up a shop again.