Trying to install the IBM JDK 64bit I came across the following error:
libstdc++.so.5 is needed by ibm-java2-x86_64-sdk-5.0-8a.0.x86_64
It turns out that yum has a neat feature to show what package provides a given component:
yum whatprovides libstdc++.so.5
gave the answer, and
yum install compat-libstdc++-33.i386
took care of installingthe missing package.