VPN Authentication Failed E=691

Hi,

I am having some problem connecting to my office VPN on MS Server 2003.

Intel MacBook CoreDuo OSX 10.4.9

Also tried Encryption "None".
Have also tried DigiTunnel Mac VPN client to no avail.

Configured on PPTP, with MS-CHAP V2.

Connection Log
Thu May 10 19:21:14 2007 : Warning: can't open options file /etc/ppp/peers/Untitled Configuration: Permission denied
Thu May 10 19:21:14 2007 : PPTP connecting to server 'xxx.xxx.xxx.com' (222.72.6.2)...
Thu May 10 19:21:19 2007 : PPTP connection established.
Thu May 10 19:21:19 2007 : Using interface ppp1
Thu May 10 19:21:19 2007 : Connect: ppp1 <--> socket[34:17]
Thu May 10 19:21:22 2007 : MS-CHAP authentication failed: E=691 Authentication failure
Thu May 10 19:21:22 2007 : Connection terminated.
Thu May 10 19:21:22 2007 : PPTP disconnecting...
Thu May 10 19:21:22 2007 : PPTP disconnected


Any help is very much appreciated.

Thanks!