The bounty is invalid because the problem description is ambiguous. However, it may be an attempt to solve the ECDLP based on Curve25519 for all instances:
http://en.wikipedia.org/wiki/Curve25519My thoughts exactly.
Is the organizer willing to offer a consolation prize to anyone who can produce a proof that the original problem is impossible given the Elliptic Curve Discrete Logarithm assumption?