Whistler wants his sword back, and it is sitting with 
Fisk in the Old Camp for 110 
ore nuggets. You are ten short, so the quest is really about prying the extra nuggets out of Whistler, buying the blade from Fisk, and carrying it back. Fisk only deals during the day, so time it right.
There is no fighting here, just a couple of conversations and the ore to pay for the sword.
- Access to the Old Camp.
- Your ore nuggets.
- Daytime, since Fisk only shows during the day.
If it is night, Fisk will not be around. Head to Mud's hut and sleep until morning, then come back out. It saves you standing around waiting.
Go through the Old Camp to Fisk, who sits on a bench, and talk to him. Choose the line about looking for a sword. He names his price at 110 ore nuggets.
Do not haggle or question the price. Pick the 'Maybe later' line and go sort out the extra ore first.
Return to Whistler and tell him Fisk wants ten more nuggets for the sword. He hands over the extra ore, which should put you at enough to buy it.
Go back to Fisk, choose the sword again, and again do not question him. When the option comes up, take it and buy the sword.
Carry the sword back to Whistler and hand it over. He is pleased to have it again, and that finishes the quest.