how to install Sagem f@st 800-840 Modem On Knoppix 3.6?

HELLO GUYS
i used to work on knoppix 3.4 n 3.6 but i never tried to install my adsl modem,
i wanna connect to internet now from knoppix 3.6 live cd , but i don have any idea on how to do it
coz i have'nt any linux driver for that , and even if i have the driver i dont know how , coz on friend told me that he got an
error wich says "cannot write/read " when he tried to make install
anyway , i hope that u can help me out like everyday ;)
thx guys
regards :D