Undefined Symbols - sqli_stmt & sqli_slct; PLS HELP

We have two RS-6000 machines. We are migrating from machine 1 to 2. Machine 1 --> Uni-processor; AIX 4.3, Informix 7.24 uc1, esql version 7.24 uc1 Machine 2 --> SMP, AIX 4.3.1, Informix 7.24 uc5, esql version 9.15 uc2 We have an application that compiles the *.ec library function files into *.o files using esql. The *.o files are then combined into a <library>.a file. The *.4gl files are first compiled into *.o and then linked with the <library>.a file to get the executable *.4ge. This process works fine on machine 1. On machine 2, the creation of <library>.a file does not result in any error messages. Next step of compiling *.4gl to *.o is OK as well. However, the liking the *.o with the <library>.a file fails with message 'Undefined symbols were found' .sqli_stmt. Some other 4gl programs also displayed .sqli_slct as undefined symbol. Upon running the final c4gl command with'-b noquiet' option, we could trace back to the .ec file that was causing the problem. The source code on the two machines is identical. When we copied the compiled <library>.a module from machine 1 to machine 2 and just ran the final linking of *.o to get *.4ge, it worked fine on machine 2. Has anyone else faced a similar problem? What are our options short of re-installing an earlier version of esql or tools? Any help would be greatly appreciated.