Explorer's Guild problem

When I go to the Explorer's Guild, a box pops up saying "Select 1 more preparation(s)" but there is nothing to select (the box is empty except for the text "When you select one of these preparations, it will be added to the list of choices..."). There is nothing to click on, so no way to get the dialog to disappear. As a result, the Explorer's Guild is unusable. I have a level 2 Blacksmith (5 slots) with 2 slots filled, so there are preparation slots available (if that makes a difference in reproducing the bug).