diff --git a/src/antidote/org/apache/tools/ant/gui/Main.java b/src/antidote/org/apache/tools/ant/gui/Main.java
index 3283e7ce8..5d8a8f648 100644
--- a/src/antidote/org/apache/tools/ant/gui/Main.java
+++ b/src/antidote/org/apache/tools/ant/gui/Main.java
@@ -70,6 +70,14 @@ public class Main {
 	 */
     public static void main(String[] args) {
         XMLHelper.init();
+
+        String vmVersion = System.getProperty("java.vm.vendor");
+        if(vmVersion.indexOf("Blackdown") > 0 &&
+           vmVersion.indexOf("RC") > 0) {
+            System.err.println("Warning: Antidote will not work with VM version Blackdown-1.3.0-RC1.");
+            System.err.println("Your version: " + vmVersion);
+        }
+
         try {
             JFrame f = new JFrame("Antidote");
             AppContext context = new AppContext(f);