The zlib-devel and zlib-devel-32bit package conflict occurs during the following upgrade path:
Upgrading an OES 2 SP3 server that has C/C++ Compiler and Tools pattern installed to OES 11 SP2 using media upgrade.
Upgrading the resultant OES 11 SP2 server to OES 11 SP3 using the channel upgrade.
Cause: These packages (zlib-devel and zlib-devel-32bit) are no longer available in the SLES 11 base.
Resolution: When you are prompted about the package conflict, uninstall them.