I'm from Italy and I have a pppoe ADSL connection too.
I configured my Mandriva Linux LE2005 with KDE and it works.
I can tell you how I made my configuration but I don't know if it will work for you...
I think you have to remove all network protocol you configured before, close session and rerun x server.
Then:
Menu -> System -> Configuration -> Configure your computer
Network and internet section, launch "configure new network interface"
Step 1: ADSL connection
step 2: normally it shows the ethernet interface, selected.
step 3: select your provider from the list; if not present, select "Not in list"
step 4: select PPP over ethernet (pppoe)
step 5: insert DNS servers of your provider (if you don't know them, I think they will be configured automatically when you connect first time, because a week ago when my provider changed them, I found them already changed in my configuration), user and password. Click on "advanced" and compile VPI and VCI as specified on your modem configuration; in my case, they are 8 and 23.
other steps: ask as you prefer.
Then you have to close session and restart x server.
In my case, i preferred not to start pppoe connection at startup.
I have netapplet (menu -> system -> monitor -> netapplet: then you choose to start netapplet at startup) on status bar, and i connect when I need.
For me it worked perfectly, and I didn't need to configure ethernet interface, it configured automatically. I hope I helped you.
Alecta
