Problem connecting under Windows 95

Has anyone encountered the following? I've had it happen at two customer sites so far. The PC is running the original version of Windows 95 and has the Informix CLI for Windows installed (it doesn't matter which version - I've tried them all). It's working fine. Then the customer downloads and installs the Microsoft Winsock 2 Update for Windows 95 because another software package needs it. That installs and seems to work (can ping, can telnet, Samba works, etc.) But now any attempt to connect to the Informix database through CLI results in an error -931, saying it cannot locate the sqlexec/tcp service. The answer is not the obvious - the "sqlexec" service *IS* specified (correctly) in c:\\windows\\services. On the off chance it would work, I copied services to c:\\windows\\system32\\drivers\\etc\\hosts (the location of the file for NT/2000/XP). It didn't help. I can't figure out why CLI now cannot find the service entry in the services file. It's definitely not just a fluke because it has now happened at two separate sites. The first time we encountered it, we just gave up and told them to upgrade their Windows 95 to XP and that worked. That was OK because it was just one PC. The second site where we just encountered it has more PC's and now they are all broken.