Have you successfully connected other USB devices?
If not ...........
But if you have then..........
You can look in the /boot/config-2.4.20-xfs file (don't edit it) and see if your modem is listed.
Do you manually set IRQ, I/O, etc. or is it done automatically?
I assume you are booting the KnoppixCD and not using a hard drive installation of Knoppix?

I don't know that it is necessary for Malaysia to be listed in the provider file. I believe that listed providers usually need special settings, commands, parameters etc. before they will work. But I know nothing about ISDN in Malaysia. post back if necessary