diff -up ./build.xml.tests-headless ./build.xml

--- ./build.xml.tests-headless	2012-03-07 11:56:41.702657823 +0100

+++ ./build.xml	2012-03-07 11:57:12.635887659 +0100

@@ -561,6 +561,7 @@

       <sysproperty key="jna.protected" value="true"/>

       <sysproperty key="jna.builddir" file="${build}"/>

       <jvmarg value="${vmopt.arch}"/>

+      <jvmarg value="-Djava.awt.headless=true"/>

       <classpath><path refid="test.runpath"/></classpath>

       <formatter type="brief" usefile="false"/>

       <formatter type="xml"/>