Index: src/net/sourceforge/pebble/web/action/AbstractCommentAction.java
===================================================================
--- src/net/sourceforge/pebble/web/action/AbstractCommentAction.java	(revision 220)
+++ src/net/sourceforge/pebble/web/action/AbstractCommentAction.java	(working copy)
@@ -47,7 +47,17 @@
 
   protected ValidationContext validateComment(Comment comment) {
     ValidationContext context = new ValidationContext();
+/*
+ * This static method call does not work when the classes are retrowoven to 1.4.
+ * The method is quite short (a single if statement) so it is imported in place
+ * of the static call.
     MailUtils.validate(comment.getEmail(), context);
+
+*/
+    if (comment.getEmail() != null && !comment.getEmail().matches("[A-Za-z0-9_.-]+@[A-Za-z0-9_.-]+\\.[A-Za-z]{2,}")) {
+      context.addError(comment.getEmail() + " is not a valid e-mail address");
+    }
+
     getModel().put("validationContext", context);
     return context;
   }
@@ -87,4 +97,4 @@
     }
   }
 
-}
\ No newline at end of file
+}
Index: build.xml
===================================================================
--- build.xml	(revision 220)
+++ build.xml	(working copy)
@@ -13,6 +13,8 @@
   <property name="javadoc.dir" value="${web.dir}/javadoc"/>
   <property name="dist.dir" value="${basedir}/dist"/>
 
+  <property name="retroweaver.home" value="G:/tmp/tmp_shortterm/retroweaver-2.0Beta2" />
+
   <property environment="env"/>
 
   <path id="project.classpath">
@@ -47,6 +49,17 @@
     <javac srcdir="${src.dir}" destdir="${classes.dir}" debug="yes">
       <classpath refid="project.classpath"/>
     </javac>
+
+    <!-- Retroweave the 1.5 classes to be 1.4 compatible -->
+    <taskdef name="retroweaver" classname="net.sourceforge.retroweaver.ant.RetroWeaverTask">
+      <classpath>
+        <fileset dir="${retroweaver.home}/lib" includes="**/*.jar"/>
+        <fileset dir="${retroweaver.home}/release" includes="**/*.jar"/>
+      </classpath>
+    </taskdef>
+
+    <retroweaver srcdir="${classes.dir}"/>
+
   </target>
 
   <target name="build" depends="compile">
@@ -102,6 +115,9 @@
         <include name="tidy.jar"/>
         <include name="xmlrpc-1.2-b1.jar"/>
       </fileset>
+      <fileset dir="${retroweaver.home}/release">
+        <include name="retroweaver-rt-2.0Beta2.jar" />
+      </fileset>
     </copy>
 
     <!-- copy license/readme information -->
@@ -153,6 +169,8 @@
       <classpath>
         <pathelement location="${classes.dir}"/>
         <pathelement path="${project.classpath}"/>
+        <pathelement location="${retroweaver.home}/release/retroweaver-rt-2.0Beta2.jar" />
+        <pathelement location="${retroweaver.home}/lib/backport-util-concurrent.jar" />
       </classpath>
 
       <formatter type="plain" usefile="false"/>