How to install Informix ODBC on Windows Server 2003/2008

Certainly a low-memory condition, possibly caused by the extremely common mistake of not closing DB connections. My recommendations are:

1. Examine the amount of non-paged pool memory available as the process runs. Odds are it will steadily decrease until the machine fails. This is an indicator that sockets aren't being closed or kernel I/O buffers aren't being freed. (unclosed sockets is more likely)
2. Check for an unknown or external Layered Service Provider (LSP) in your winsock stack via 'net sh winsock catalog > wsockcat.txt'. Compare the output to your other Windows servers. Suspect first any providers that have been inserted into your stack that originate outside of mswsock.dll.
3. If low non-paged pool is the problem see if restarting the application or either DB server releases memory. You're likely not using connection pooling, so 'sp who' and 'list applications' might show interesting results if some DB access layer is leaving old connections open.

If you do see the DB servers reporting a high number of idle connections in #3 you may be able to mitigate the problem by writing scripts to actively shutdown unused connections from the server side of the socket.

Named pipes and TCIP protocols for SQL server 2005 are disabled by default. Have you enabled them under "SQL server configuration manager"? You can find the protocols in the SQL Server Network configuration and under SQL Native client xx configuration.

The connection on the server itself works thanks to the "Shared memory" protocol.