pppoe comes up - but can't reconnect

[David Banning]

My pppoe connection connects just fine, and stays connected often
for weeks - then my service provider may have a hiccup and when my
system attempts to reconnect, or when I attempt to reconnect manually
I get an error - here is what appears in my error logs when attempting 
to connect unsuccesssfully - /var/log/messages;

Apr 26 03:38:57 3s1 kernel: tun0: link state changed to UP
Apr 26 03:40:38 3s1 kernel: tun0: link state changed to DOWN
Apr 26 03:40:51 3s1 kernel: tun0: link state changed to UP
Apr 26 03:40:54 3s1 ppp[90150]: tun0: Warning: iface add: ioctl(SIOCAIFADDR, 209.161.205.12 -> 216.154.64.1): File exists
Apr 26 03:40:54 3s1 ppp[90150]: tun0: Error: ipcp_InterfaceUp: unable to set ip address

In my ppp.log I get this;

pr 26 16:49:03 3s1 ppp[94945]: tun0: Phase: deflink: opening -> dial
Apr 26 16:49:03 3s1 ppp[94945]: tun0: Phase: deflink: dial -> carrier
Apr 26 16:49:04 3s1 ppp[94945]: tun0: Phase: Received NGM_PPPOE_ACNAME (hook "bas1-toronto27")
Apr 26 16:49:04 3s1 ppp[94945]: tun0: Phase: Received NGM_PPPOE_SESSIONID
Apr 26 16:49:04 3s1 ppp[94945]: tun0: Phase: Received NGM_PPPOE_SUCCESS
Apr 26 16:49:04 3s1 ppp[94945]: tun0: Phase: deflink: carrier -> login
Apr 26 16:49:04 3s1 ppp[94945]: tun0: Phase: deflink: login -> lcp
Apr 26 16:49:05 3s1 ppp[94945]: tun0: Phase: bundle: Authenticate
Apr 26 16:49:05 3s1 ppp[94945]: tun0: Phase: deflink: his = PAP, mine = none
Apr 26 16:49:05 3s1 ppp[94945]: tun0: Phase: Pap Output: -obscured--------- ********
Apr 26 16:49:07 3s1 ppp[94945]: tun0: Phase: Pap Input: SUCCESS ()
Apr 26 16:49:07 3s1 ppp[94945]: tun0: Phase: deflink: lcp -> open
Apr 26 16:49:07 3s1 ppp[94945]: tun0: Phase: bundle: Network
Apr 26 16:49:07 3s1 ppp[94945]: tun0: Warning: iface add: ioctl(SIOCAIFADDR, 209.161.205.12 -> 216.154.64.1): File exists
Apr 26 16:49:07 3s1 ppp[94945]: tun0: Error: ipcp_InterfaceUp: unable to set ip address
Apr 26 16:49:07 3s1 ppp[94945]: tun0: Phase: bundle: Terminate
Apr 26 16:49:07 3s1 ppp[94945]: tun0: Phase: deflink: open -> lcp
Apr 26 16:49:07 3s1 ppp[94945]: tun0: Phase: deflink: Disconnected!
Apr 26 16:49:07 3s1 ppp[94945]: tun0: Phase: deflink: lcp -> logout
Apr 26 16:49:07 3s1 ppp[94945]: tun0: Phase: deflink: logout -> hangup
Apr 26 16:49:07 3s1 ppp[94945]: tun0: Phase: deflink: Disconnected!
Apr 26 16:49:07 3s1 ppp[94945]: tun0: Phase: deflink: Connect time: 4 secs: 119 octets in, 144 octets out

My first thought was to go to the error line which states "File exists" - and 
to delete that file - but I have not idea where that is.  Here is my ppp.conf;

default: # or name_of_service_provider
      set device PPPoE:fxp0 # replace xl1 with your ethernet device
      set mru 1492
      set mtu 1492
      set authname ??????????????????
      set authkey ??????
      set log Phase tun command # you can add more detailed logging if you wish
      disable ipv6cp
      set dial
      set login
      set ifaddr 10.0.0.1/0 10.0.0.2/0
      set ifaddr 209.161.205.12 206.221.248.4
      add default HISADDR
      nat enable yes # if you want to enable nat for your local net

the line
      set ifaddr 209.161.205.12 206.221.248.4
states my statis IP address followed by the connection address at my
sevice provider I am guess - but my service providers address changes
right now it is 216.154.64.1

Any pointers or comments would be useful.