The name service (named) was not properly reloaded after a node was added with insert-ethers. The issue is with the configuration file /etc/rndc.conf from the bind package found on RHEL 4 update 3 and 4.
The fix is to replace the stock /etc/rndc.conf file with a known good one.
On uni-processor nodes, the symbolic link to the kernel build environment /usr/src/linux-2.6 was not properly set.
This is fixed by adding the configuration script /etc/rc.d/rocksconfig.d/pre-10-prep-kernel-source which runs after the buggy configuration script /etc/rc.d/rocksconfig.d/pre-09-prep-kernel-source.