A PPPOE Problem

I've downloaded an ISO file of Ubuntu and installed it. but there is a problem with my PPPOE setting. the texts in below is my operats. Could any one tell me what's wrong with my ADSL Modem? How to solve it? thanks!

[quote]
lamuna@Lamuna2:~$ pon
/usr/sbin/pppd: In file /etc/ppp/peers/provider: unrecognized option '/dev/modem'

lamuna@Lamuna2:~$ pppconf
bash: pppconf: command not found

lamuna@Lamuna2:~$ sudo pppoeconf
Password:
Plugin rp-pppoe.so loaded.

lamuna@Lamuna2:~$ pon dsl-provider
Plugin rp-pppoe.so loaded.

lamuna@Lamuna2:~$ plog
Sep 24 22:51:01 Lamuna2 pppd[6016]: Connect: ppp0 <--> eth0
Sep 24 22:51:02 Lamuna2 pppd[6016]: Remote message: 18;User(username********) Checking LoginUser RBillServer, r
Sep 24 22:51:02 Lamuna2 pppd[6016]: PAP authentication failed
Sep 24 22:51:02 Lamuna2 pppd[6016]: Connection terminated.
Sep 24 22:51:12 Lamuna2 pppd[4341]: PPP session is 7696
Sep 24 22:51:12 Lamuna2 pppd[4341]: Using interface ppp0
Sep 24 22:51:12 Lamuna2 pppd[4341]: Connect: ppp0 <--> eth0
Sep 24 22:51:13 Lamuna2 pppd[4341]: Remote message: 18;User(username********) Checking LoginUser RBillServer, r
Sep 24 22:51:13 Lamuna2 pppd[4341]: PAP authentication failed
Sep 24 22:51:13 Lamuna2 pppd[4341]: Connection terminated.

lamuna@Lamuna2:~$ ifconfig ppp0
ppp0: error fetching interface information: Device not found

lamuna@Lamuna2:~$ sudo pon
/usr/sbin/pppd: In file /etc/ppp/peers/provider: unrecognized option '/dev/modem'

lamuna@Lamuna2:~$ sudo pon dsl-provider
Plugin rp-pppoe.so loaded.
[/quote]