I am getting the following error the first time I open the craft window after logging in/reloading UI.

Interface/AddOns/CraftSim/Data/DataExport.lua:584: bad argument #1 to 'pairs' (table expected, got nil)

This is occurring on multiple characters. The error appears to be coming from GetProfessionGearStatsByLink

I will look at this when I got time, maybe I can fix it for the next release :)

Up til now I could not reproduce it (1.7.7)

I will close this issue until it occurs again

The error itself stopped popping up with one of the recent updates, although one of the symptoms is still happening: On first opening a craft window, the CraftSim windows do not display properly.

This is how the window looks when I first open the craft:

After closing and re-opening or changing tabs, the windows display properly:

Since the error message no longer appears and doesn't need to be closed, the issue is less disruptive.