Are you sure it's a problem with the hardware? Have you checked the software? Post your sketch, maybe the forum finds an issue there. Which version of the IDE do you use?
It will go into a loop and not accept a DHCP Lease,
I can see the Router trying to send a valid response. It just doesn't accept / see it.
I am currently using 1.0.1
I assume it is not possible to enable a software reset of the Ethernet? Although I do see that pin 59 on the Wiznet is a Reset pin.
From their documentation.
RESET Pin# 59
This pin is active Low input to initialize or re-initialize
By asserting this pin low for at least 2us, all internal
registers will be re-initialized to their default states.