Broadband provider
ISP/package: Streamyx 512kbps
Location: Cheras

Modem: RIGER DB102
Router: Level One WBR-3406TX wifi router

Problem description:
1. I set the DB102 to PPPOE connection, and yes it can connect to internet, i can surf net no problem
2. I connect the DB102 to Wifi router (Level One WBR-3406TX, router IP=192.168.123.254). But then I only can access to wifi router page, 192.168.123.254, i am not able to access DB102 page 192.168.1.1, so I cannot to the internet

Previously, I was using Aztech ADSL router modem, and with this same wifi router as well, after connected both ADSL and Wifi router, I can access both 192.168.123.154 and 192.168.1.1, then i can disconnect/reconnect streamyx in the 192.168.1.1

Recently my Aztech modem has gone(5 yrs old already), then i got this DB102, I wonder why the same PPPOE connection, with Aztech i have no problem, but with DB102, i cannot connect to Internet?
I think the Wifi router not able to connect with DB102, because in wifi page shown [Gateway: unreachable]

What happen? something wrong with DB102? or with Wifi router???
Anyone can help me???