Error while gw_gethostbyname occurs.

Not one I've seen before, but we now have two machines that are failing 
to resolve lookups to connect to http servers (when receiving an inbound 
message) due to gethostbyname failing.

Potentially I think this could be a memory issue, but has anyone else 
any ideas (nslookup works, dig works etc, /etc/resolv.conf is correct etc.)?

2005-08-16 08:43:36 [26170] [9] ERROR: Error while gw_gethostbyname occurs.
2005-08-16 08:43:36 [26170] [9] ERROR: System error 2: No such file or 
directory
2005-08-16 08:43:36 [26170] [9] ERROR: gethostbyname failed
2005-08-16 08:43:36 [26170] [9] ERROR: error connecting to server 
`www.ourserver.com' at port `80'
2005-08-16 08:43:36 [26170] [9] ERROR: Couldn't send request to 
<http://www.ourserver.com:80/servlet/Something?from=%2B4477777777&sms=Test>

Regards

Alex