I tried to find some more information on this phone on the UK website and was unable to - however it is on the Nokia US website.
If you've localised the issue to a definite aerial problem then you will have to take it to your nearest Nokia Service Centre to get it repaired. If you attempt to repair or replace it yourself you will invalidate your warranty.
Hope this helps.
Message Edited by edwardquan on 30-Mar-200710:26 PM
Regards,
Edward