If director/ gets removed (e.g. so it gets updated) from the Buckminster_3.x/ folder, builds fail. Thus the plug-in may check if director/ is available and install it if not.

[Buckminster_3.6] $ /opt/hudson/tools/Buckminster_3.6/director/director -vm /opt/hudson/tools/Java1.5_update_22_x86-64/bin/java -d /opt/hudson/tools/Buckminster_3.6/buckminster -p Buckminster -r "http://download.eclipse.org/tools/buckminster/headless-3.6/, http://download.cloudsmith.com/buckminster/external-3.6" -uninstallIU "org.eclipse.equinox.p2.director.feature.feature.group, org.eclipse.buckminster.psf.feature.feature.group, org.eclipse.buckminster.emma.headless.feature.feature.group, org.eclipse.buckminster.pde.headless.feature.feature.group, org.eclipse.buckminster.subclipse.headless.feature.feature.group, org.eclipse.buckminster.maven.headless.feature.feature.group, org.eclipse.buckminster.core.headless.feature.feature.group, org.eclipse.buckminster.git.headless.feature.feature.group, org.eclipse.buckminster.cvs.headless.feature.feature.group" -installIU "org.eclipse.equinox.p2.director.feature.feature.group, org.eclipse.buckminster.psf.feature.feature.group, org.eclipse.buckminster.emma.headless.feature.feature.group, org.eclipse.buckminster.pde.headless.feature.feature.group, org.eclipse.buckminster.subclipse.headless.feature.feature.group, org.eclipse.buckminster.maven.headless.feature.feature.group, org.eclipse.buckminster.core.headless.feature.feature.group, org.eclipse.buckminster.git.headless.feature.feature.group, org.eclipse.buckminster.cvs.headless.feature.feature.group"
ERROR: Cannot run program "/opt/hudson/tools/Buckminster_3.6/director/director" (in directory "/opt/hudson/tools/Buckminster_3.6"): java.io.IOException: error=2, No such file or directory

A workaround is to remove Buckminster_3.x/ completely to have the director/ reinstalled.

Thanks