Why are the new leaves on my young daphne plant curling?

Possibly a little late to answer your question!
But I stumbled across it through a google search seeking the same answer,
if you haven't used any sprays around the vicinity of the plant, the consensus is to look for aphids. Those tiny little bugs seem to suck the sap of the daphne and favour the young leaves causing the curl. Blast the critters off with the garden hose, but take it easy using chemicals and only use them if the infestation is out of control.

I found this site helpful -
http://gardening.yardener.com/YardenersPlantHelper/LandscapePlantFiles/FilesAboutShrubs/ShrubFiles/Daphne/ProblemsofDaphne