When executing JCL’s in 64 bit server enterprise edition all JCLs fail with "Program Not found" S806 error even though the JES program Path for the directory containing executable files to be run by JCL jobs . When creating a new server in 32 bit mode and running the same JCL with the JES path pointing to the same folder, the job found the program and ran fine. Whereas, creating a new server with same settings but 64 bit mode, the job failed with Program not found (S806) when run in the 64 bit server.

You cannot run programs compiled and /linked on 32-bit platforms or 32-bit mode in a 64-bit run time system. To execute the program in a 64-bit run-time environment, recompile the program as 64-bit to run in the 64 bit server enterprise edition.