Cisco Ip Phone not working on D link setup

Cisco Ip Phone not working on D link setup

User has a home network setup using Cisco Router and D link Ethernet Kid
setup. I send him a Cisco IP phone 7965 which was configured to work thru
VPN connection. User is not able to get the phone to work when connecting
thru Dlink. I did some troubleshooting and from IP address that he has on
the phone looks like phone is not getting connection. I ask him to plug in
the phone direclty to Cisco Router. He did and phone workded perfectly
fine!
the problem is that his office is setup on 2nd floor but his Router is
setup on the 1st floor. and he using Dlink to pull the signal from the 1st
to 2nd floor. Is any one familiar with Dlink setup? Is there any
configuration that I can do remotely on Dlink to allow connection to the
IP phone? What is my other option??
Urgent please.
Any information will be appriciated. Thank you, Serge