Radwulf is concerned with providing for the horses of the camp and wants you to see to their needs of food and water.
'It is my duty to see to the needs of our horses. It is a task I relish, for I know its importance: the success of our mission depends in no small part on them!
'When Langmanu and Swithlic fled from the Orcs, their saddlebags must have fallen from their backs; they did not return with them. I kept much of their feed in those bags. Search the woods between this camp and where you found my friends, south-east of here, for their fallen saddlebags.
'Food is not enough. They will need water as well, but I do not trust the streams here; too many Orc-boots muddying the waters. You saw a waterfall on your way to rescuing my friends, I know, but there are a lot of dead Orcs lying in that stream. If you follow the river upstream, though, where the water flows from much higher ground, perhaps you can get fresh water from the waterfall before it flows past those bodies. Take this waterskin and fill it at that waterfall. That way my friends will have fresh, clean water to drink.'
Radwulf gave you a water-skin to fill at the waterfall south-east of Mansig's encampment. He also wants you to search the ground between the camp and where you found the horses for their fallen saddlebags.
Radwulf is at the Rohirrim camp in the East Wall.
You have found the fallen saddlebags and filled the water-skin given to you by Radwulf and should now return to the Rohirrim horse-master.