DIR-635 cannot update WAN IP to dlinkdns Dynamic DNS service

Device name: D-Link DIR-635
Firmware version: 1.09, 2006/10/23
Hardware version: A1

Every time I enable this service on the web UI, it will be disabled immediately with following log:
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WARN] Sat Oct 25 16:22:54 2008 Error updating dynamic DNS entry: blairsu.dlinkddns.com abuse. Please check configuration. Disabling DynDNS
[INFO] Sat Oct 25 16:22:53 2008 Updating dynamic DNS entry due to timeout
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Actually, I have the same problem with DynDNS.org, and I received a mail from Dyndns with title "Hostname Blocked Due To Abuse". The reason is "receipt of multiple updates originating from the same IP address."