The option to trade 4 balls of wool for 1 rope is not available.
Ned has the id (918)
Are you supposed to be able to trade balls of wool for rope?
I thought you could just get rope for free, and use the balls of wool to make a wig for the quest?
Even the wiki doesn't mention about trading one for the other :/? (oh okay apparently it does mention that, perhaps the guide for prince ali's rescue was wrong.)
Yes, you are supposed to be able to trade them.
It is even referenced in npc dialogue during Fremennik isles.