We cannot start our CICS Region becasuse of an error pointing to the Oracle XA module.

The customer was using Enterprise Server v5.1 WrapPack5 under RHEL with Oracle 11.1.0.6.   As the Test CICS region started they saw error message, CASXO0002S Switch Load Module for resource XAORACLE failed to load. Their CICS Development region started without error. We checked the ORACLE_HOME, COBPATH and LD_Library_Path 
environment variables and all were fine. 

Using the command 'lld ESORAXA.so", showed a missing module from Oracle. Checking the development server the module was there but it was missing from the Test Region. 
 
Starting with Oracle v11.2, Oracle stopped shipping their 32-bit modules meaning customers must use the v11.1.0.6 ones making sure they have all the required 32-bit modules from Oracle.
 
 Added for reference:
 
The ldd command will try to load all the support modules for that .so
 
[support@lorince5568]$ ldd ESORAXA.so
        linux-gate.so.1 =>  (0xffffe000)
        libclntsh.so.11.1 => /home/products/oracle/product/11.2.0/client_1/lib/libclntsh.so.11.1
(0xf6263000)
        libdl.so.2 => /lib/libdl.so.2 (0xf624e000)
        libm.so.6 => /lib/libm.so.6 (0xf6227000)
        libpthread.so.0 => /lib/libpthread.so.0 (0xf6210000)
        libnsl.so.1 => /lib/libnsl.so.1 (0xf61f8000)
        libc.so.6 => /lib/libc.so.6 (0xf60b4000)
        libaio.so.1 => /usr/lib/libaio.so.1 (0xf60b2000)
        /lib/ld-linux.so.2 (0x001cd000)
 
The file command will tell us if it is built correctly
 
[support@lorince5568]$ file ESORAXA.so
ESORAXA.so: ELF 32-bit LSB shared object, Intel 80386, version 1 (SYSV), not stripped