D4GL 3.0 & OnLine 5.10

We are upgrading to Dynamic-4GL 3.00.UC1 (on an RS6000 running AIX 4.3.1) We're using the product with OnLine 5.10.UC1 The D4GL 3.0 User Guide (page 2-7) recommends installing Client-SDK even if the GLS features aren't needed. We downloaded the freeware and installed it (following the Informix Clients Products Installation Guide) as "root", running the ./installclientsdk script. The install SEEMED to go well, as did the subsequent install of D4GL 3.0, and the compile of the runner with our additional C-functions. Now, our D4GL programs won't run, error number -25560. "Environment variable INFORMIXSERVER must be set." (But we're running OnLine 5.10 , remember.) Infx Tech support suggesting setting it the the DBSERVERNAME listed in our tbconfig file, and adding a line in our sqlhosts file with that DBSERVERNAME and "olipcpip" and our machine name and "sqlexec", and adding a line with "sqlexec" and "1526/tcp" to the /etc/services file. But now, that just gives us error # -25584. "Network driver cannot access the server program /usr/informix/lib/sqlexec" (because there is no such animal). The classic-4GL versions of the same programs still run fine. Should we have ignored the book's advice to download the Client-SDK? Our ESQL/C verion before the upgrade was 5.10.UC1. Guess what? Now it is 9.21.UC1.