Newer Linux distributions use libraries that are incompatible to those used by the ELDK's installation tools. A solution for this problem will be available in the next release of the ELDK (version 3.0). Until then, the following back-port is available:
Please download the file ftp://ftp.denx.de/pub/tmp/ELDK-update-2.2.0.tar.bz2
Then change into the source tree with the ELDK files and perform the following operations:
bash$ rm RPMS/rpm-4.0.3-1.03b_2.i386.rpm \
bash$ tar jxf /tmp/ELDK-update-2.2.0.tar.bz2
Then build the ISO image as documented, and try again.