[Ant]Installer.rpm Build failed

Hi, everyone, I build openfire in Fedora core 6 mathine, and I had installed JDK1.6.0 in there, but when I built a rpm installer with Ant file in the openfire project, I met a failed about JDK, any help here? Thanks for your all!

console output as: — ‘ /ftp-dir/ManifoldServer’ was the folder where I put my openfire project in

Buildfile: /ftp-dir/ManifoldServer/build/build.xml
init:
dist.init:
installer.rpm:
init:
dist.init:
javadoc:
-i18n:
dist.src:
[tar] Nothing to do: /ftp-dir/ManifoldServer/target/release/openfire_src_3_6_4.tar.gz is up to date.
[rpm] Building the RPM based on the openfire.spec file
[rpm] Executing(%prep): /bin/sh -e /var/tmp/rpm-tmp.21490
[rpm] + umask 022
[rpm] + cd /ftp-dir/ManifoldServer/work/rpm/BUILD
[rpm] + LANG=C
[rpm] + export LANG
[rpm] + unset DISPLAY
[rpm] + cd /ftp-dir/ManifoldServer/work/rpm/BUILD
[rpm] + rm -rf openfire_src
[rpm] + /bin/gzip -dc /ftp-dir/ManifoldServer/work/rpm/SOURCES/openfire_src_3_6_4.tar.gz
[rpm] + tar -xf -
[rpm] + STATUS=0
[rpm] + ‘[’ 0 -ne 0 ‘]’
[rpm] + cd openfire_src
[rpm] ++ /usr/bin/id -u
[rpm] + ‘[’ 0 = 0 ‘]’
[rpm] + /bin/chown -Rhf root .
[rpm] ++ /usr/bin/id -u
[rpm] + ‘[’ 0 = 0 ‘]’
[rpm] + /bin/chgrp -Rhf root .
[rpm] + /bin/chmod -Rf a+rX,u+w,g-w,o-w .
[rpm] + exit 0
[rpm] Executing(%build): /bin/sh -e /var/tmp/rpm-tmp.23492
[rpm] + umask 022
[rpm] + cd /ftp-dir/ManifoldServer/work/rpm/BUILD
[rpm] + cd openfire_src
[rpm] + LANG=C
[rpm] + export LANG
[rpm] + unset DISPLAY
[rpm] + cd build
[rpm] + ant openfire
[rpm] Buildfile: build.xml
[rpm] init:
[rpm] BUILD FAILED
[rpm] /ftp-dir/ManifoldServer/work/rpm/BUILD/openfire_src/build/build.xml:239: Must use JDK 1.5.x or higher to build Openfire
[rpm] Total time: 2 seconds
[rpm] error: Bad exit status from /var/tmp/rpm-tmp.23492 (%build)
[rpm] Bad exit status from /var/tmp/rpm-tmp.23492 (%build)
[rpm] RPM build errors:

BUILD FAILED
/ftp-dir/ManifoldServer/build/build.xml:1095: ‘/usr/bin/rpmbuild’ failed with exit code 1

Total time: 17 seconds