I try to set up my DSL connection on a Debian 4.0 notebook following the instructions 'Configuration of PPP Over Ethernet (PPPoE) for Debian Linux'. It failed to detect my ISP, responsed this:

NOT CONNECTED
│ │
│ Sorry, I scanned 1 interface, but the Access │
│ Concentrator of your provider did not respond. Please │
│ check your network and modem cables. Another reason │
│ for the scan failure may also be another running pppoe
│ process which controls the modem.

any ideas how I can fix it?

also, I do have pppoeconf (pppoe and ppp) installed, pppoeconf can see eth0, it just won't promote me to enter ISP/Password info.