I managed under all three distros with pppoeconf. In Kubuntu and
Feather Linux the connection seems to be set to DHCP by default, so it
connected without trouble. Under Yamefa I disabled roaming mode, set
the connection to DHCP and then ran pppoeconf but when typing the
username and password I had to press Shift.

I could boot Yamefa in safe graphics mode ("Demarrer en mot
graphique sans echec"). It is very interesting and nicely decorated but
I will not use it.

I am writing under Damn Small Linux.