Sometimes when a component product is installed, one of the necessary RPMs for the uninstallation, sun-entsys-uninstall-l10n-2.0-1, does not get installed.
Solution Manually install the missing uninstall RPM by doing the following:
# rpm -i sun-entsys-uninstall-2.0.i386.rpm
After installing the RPM, the uninstall script will appear.