I’ve enabled Expert Mode. Please help me.
Weird… Is it still same? I’d checked that your account enabled Expert Mode. Please try to log out and sign in again if it’s still same.
Even if it’s same, please try to access the menu directly via http://mudfish.net/admin/item/mine/add/-1 link.
I don’t know how, but it is now showing. Sorry for the trouble!
Cool! 
I hope now everything goes well with mudfish. Please let me know if there are any other problems.