VPN connections crash my server

Hi guys I'm having a problem with my server which is causing me to loose sleep.....not good :( Whenever a VPN client connects into my server, this appears in the log: Oct 11 14:08:49 server pppd[610]: DSAccessControl plugin: User 'xxxx' authorized for access\n Oct 11 14:08:49 server pppd[610]: Unsupported protocol 0x8057 received Oct 11 14:08:49 server pppd[610]: local IP address 192.168.1.10 Oct 11 14:08:49 server pppd[610]: remote IP address 192.168.1.201 Oct 11 14:08:52 server DirectoryService[42]: Search connection failure: During an attempt to bind to [127.0.0.1] LDAP server. Oct 11 14:08:52 server DirectoryService[42]: Search connection failure: Disabled future attempts to bind to [127.0.0.1] LDAP server for next 0 seconds. Oct 11 14:08:52 server servermgrd: servermgr_dns: Reloaded named Oct 11 14:08:55 server pop3[508]: login: [192.168.1.101] xxxxxxx APOP User logged in Oct 11 14:09:00 server pppd[610]: Connection terminated. Oct 11 14:09:00 server pppd[610]: L2TP disconnecting...\n Oct 11 14:09:00 server pppd[610]: L2TP disconnected\n Oct 11 14:09:00 server vpnd[601]: --> Client with address = 192.168.1.201 has hungup\n Oct 11 14:09:03 server servermgrd: servermgr_dns: Reloaded named Obviously the enries in the log from DirectoryService are cause for concern and they appear during most VPN connections in from the outside world. 9 times out of 10, connections and disconnections cause no problems but 1 connection in 10 causes all authentication to the server (mail, AFP, ARD, etc) to fail completely and the only solution I have is to restart the server. On a headless Xserve running a hardware RAID card this is obviously not a good option. The server itself is running it's own DNS, Mail, NetBoot, AFP, Open Directory and of course VPN services. DNS appears to be working correctly, DHCP too is good with no overlapping IP addresses. All appears normal. Can anyone suggest a solution ? Thanks