Hi dear..
U can kill that process......
first give command
#ps -A
it shows all process which are currently active...
from there give command
#kill -9 pid
(where pid is the process id of ppoe process)....
After that i think it will work...
Suppse after that it will not work.., then better to ask RICKY, may be he knows , as RICKY is expert....
Gaurav