Kina's Gratitude Crystals Glitch?

The sidequest becomes available only after you complete the fire sanctuary. Once this is done, Guld will be waiting on top of one of the rock pillars as you dive underground at the base of Eldin volcano. If Guld is not there, then that means you haven't completed enough of the story yet. Guld will mention something about it being too hot to find treasure when the sidequest is available.

Here is the entrance to the location by Eldin Volcano you must dive to find Guld, in case it was hard to understand what I was talking about:

UPDATE: Also, I think you have to complete all the jobs that Pumm, the owner of the Lumpy Pumpkin, has for you.