Setting up vpnd

I've followed the instructions in the vpnd article to the letter, but it doesn't work! When I try connecting via PPTP, I get the message "Authentication failed". In the log file, it says (I've taken out my IP address): pppd[529]: PPTP incoming call in progress from 'nnn.nnn.nnn.nnn'... mach_kernel: pptp_wan_attach, link index = 0, (ld = 0x1acb304) pppd[529]: PPTP connection established. pppd[529]: Using interface ppp0 pppd[529]: Connect: ppp0 <--> socket[34:17] pppd[529]: Warning - secret file /etc/ppp/chap-secrets has world and/or group access pppd[529]: MSCHAP-v2 peer authentication succeeded for pflvpn pppd[529]: MPPE 128 bit, stateless compression enabled pppd[529]: Could not determine local IP address pppd[529]: Connection terminated. pppd[529]: Connect time 0.1 minutes. pppd[529]: Sent 605 bytes, received 332 bytes. pppd[529]: PPTP disconnecting... pppd[529]: PPTP disconnected pppd[529]: Exit. Any ideas?