Interesting, the log says:
:info:build /opt/local/share/java/apache-ant/bin/ant: line 332: /opt/local/share/java/openjdk6_bootstrap/jre/bin/java: Bad CPU type in executable
:info:build /opt/local/share/java/apache-ant/bin/ant: line 332: /opt/local/share/java/openjdk6_bootstrap/jre/bin/java: Unknown error: 0
:info:build /opt/local/share/java/apache-ant/bin/ant: line 332: /opt/local/share/java/openjdk6_bootstrap/jre/bin/java: Bad CPU type in executable
:info:build /opt/local/share/java/apache-ant/bin/ant: line 332: /opt/local/share/java/openjdk6_bootstrap/jre/bin/java: Unknown error: 0
But because this was not a clean attempt, could you please clean and try again?