It's not a duplicate key. It's a foreign key with the same name.
Check the subscriber database for objects with that name. If you find one, either drop it (if it's the same foreign key that the replication is trying to create) or rename it.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability