diff --git a/pdf/plugin.jelly b/pdf/plugin.jelly
index 206b9e10..49f6e2a6 100644
--- a/pdf/plugin.jelly
+++ b/pdf/plugin.jelly
@@ -260,6 +260,7 @@ plugin.currentVersion           = [${plugin.currentVersion}]
       <sysproperty key="javax.xml.parsers.DocumentBuilderFactory" value="org.apache.xerces.jaxp.DocumentBuilderFactoryImp"/>
       <sysproperty key="javax.xml.parsers.SAXParserFactory" value="org.apache.xerces.jaxp.SAXParserFactoryImpl"/>
       <sysproperty key="java.endorsed.dirs" path="${java.home}/lib/endorsed;${maven.home}/lib/endorsed}"/>
+      <jvmarg value="-Djava.awt.headless=true"/>
       <classpath>
         <pathelement location="${plugin.getDependencyPath('xerces:xercesImpl')}"/>
         <pathelement location="${plugin.getDependencyPath('xalan')}"/>
@@ -305,6 +306,7 @@ plugin.currentVersion           = [${plugin.currentVersion}]
     <echo>Generating ${internal_pdf_workingDir}/${maven.pdf.pdfName} ...</echo>
     <echo>Config file: ${internal_pdf_workingDir}/userconfig.xml</echo>
     <java classname="org.apache.fop.apps.Fop" fork="true" failonerror="true">
+      <jvmarg value="-Djava.awt.headless=true"/>
       <sysproperty key="javax.xml.transform.TransformerFactory" value="org.apache.xalan.processor.TransformerFactoryImpl"/>
       <!-- System proxies for jdk 1.5+ -->
       <sysproperty key="java.net.useSystemProxies" value="true"/>
diff --git a/pdf/xdocs/changes.xml b/pdf/xdocs/changes.xml
index 417daeba..b988004b 100644
--- a/pdf/xdocs/changes.xml
+++ b/pdf/xdocs/changes.xml
@@ -25,6 +25,7 @@
   </properties>
   <body>
     <release version="2.5.1-SNAPSHOT" date="in SVN">
+      <action dev="aheritier" type="fix">Error "Can't connect to X11 window server" on Unix.</action>
       <action dev="ltheussl" type="fix" issue="MPPDF-57">Unable to remove cover type and version.</action>
     </release>
     <release version="2.5" date="2006-07-21">
