You gathered the necessary supplies for the Lossoth sled-builders, but they still need salt to cure the hides.
'Now that we have all of our raw materials, we are ready to build the sleds. However, our rawhide will never hold the wood together if it is not cured first. Curing the rawhide dries it and makes it last longer.
'First, we will need some suola -- salt, the Kivi-väki call it. The Kivi-väki bring it from a place known only in stories, where mouths rise out from the earth. These traders are the only ones who are able to gather it. Trade them a set of antlers for a satchel of suola, then place it in the curing barrel with the rawhide strips.
'If you do this for me, you will have proven yourself a friend to the kelkka-makers of the Lumi-väki.'
Ofráth can be found along the road south of Kauppa-kohta.
Eija has asked you to go to the dwarves and trade a set of antlers for a satchel of salt to help in the hide-curing process.
The curing barrel is next to Eija in Kauppa-kohta's shoreline sled-building camp.
Now that you have obtained a satchel of salt from the dwarves, you should return to Eija and place it in the curing barrel.
Eija is in Kauppa-kohta's sled-building camp, at the lake's eastern shore.
Having started the curing process for the rawhide, you should speak with Eija once more.