[Openswan Users] nat-t causes 'ERROR: asynchronous network error'

[No body is Perfect]

This was XP behind nat-t connecting to an office network with openswan, 
xl2tpd-1.1.05 and openswan 2.4.6 and newer.
Openswan 2.4.4 with l2tpd-0.69-13 no problem. any ideas ?

ERROR: asynchronous network error report on eth1 (sport=4500) for message to 
89.12.146.134 port 4500, complainant 217.110.17.180: No route to host [errno 
113, origin ICMP type 3 code 1 (not authenticated)]