The buckminster plugin relies on the 'java' executable being in the system path variable.
That raises 2 issues:
1. If java is not in the path, the plugin cannot be used
2. You cannot use another java than the one in the system path

Steps to reproduce:
1. remove the path to the java executable from the system's path
2. execute any build with a buckminster build step

Solution:
The plugin needs to get the full path to java from hudson

More Information:
http://www.eclipse.org/forums/index.php?t=msg&th=158715&start=0&S=60f5913f2ff7808b5a6e242a548e855f