Unfortunately i've just spotted another issue on s390x the location of libjvm.so seems to be
/usr/lib/jvm/java-6-openjdk-s390x/jre/lib/s390x/serverHowever java-arch.sh appears to (from looking at the code and looking at build logs, I don't have access to a s390x machine myself) return "s390" on s390x systems.