I use rp-pppoe and I had problems resolving hostnames - it made
/etc/resolv.conf point to rp-pppoe's resolv.conf which turned out to be
unreadable by normal users - chmod'ing it a+r fixed it.  I don't know
if this is your problem or not, but I figured I'd add it in case
someone else had the same problem.

-- 
Steve Tremblett