Linksys and Smartphone

Hi all,

I have purchased a htc touch pro which is working fine. However the G3
connection is poor, due to dutch provider KPN, and most of the time it
switches to GPRS. To improve the internet connection to the mobile phone I
use a usb cable from phone to PC. Again that works fine. Then I purchased a
Cisco Linksys Wireless-N broadband Router and connected it between my DSL
modem and the router like it says in the book. The phone now can 'see' the
router and on the phone I connect to the router with name and password. The
connection stays ON for a couple of seconds and then disconnects. Whatever
protocol I select, no proper result. Does anyone knows what I do wrong or
oversee.
Regards,