At last my router is fixed. I took it to the local agent Alris Technology in person and they found that I should have upgraded the firmware in order to work here in Hong Kong with the biggest ISP in town Netvigator.
How would I know that? D-Link is from the US and I visited their website and had few emails with their technical support on this issue, isn't this natural course of actions? It turned out that from the technical support here from Alris I should have gone to D-Link's Taiwan download site here or Taiwan D-Link distributor's site here for assistance!
Again how would I know that? There is a Quick Installation Guide in the box which tells me support information, there are websites for Australia, Singapore and US....none for Taiwan. By the way that quick installation guide isn't well written.
Now I have no problem connecting using PPPoE and the configuration shows that I still have firmware 1.0 which is all in Chinese. From the Taiwan site here there is a download for version 1.01_060126 which I don't know if I should download and upgrade. I have written to Alris on this for advice!