Clicking the Setnet32 button does not launch setnet32
Setnet32 is part of the Informix Client SDK. The Informix Client SDK is required to use the Informix connection on Windows. The SDK is not part of the Querix tools distribution. Please download and install the Informix Client SDK from IBM.
If these are already installed, try loading Setnet32 directly i.e. in Windows from the Start Menu.
Start → Informix Connect → informix setnet32