Index: src/main/java/hudson/tasks/Ant.java
===================================================================
--- src/main/java/hudson/tasks/Ant.java	(revision 11250)
+++ src/main/java/hudson/tasks/Ant.java	(working copy)
@@ -121,15 +121,17 @@
         String normalizedTarget = targets.replaceAll("[\t\r\n]+"," ");
 
         AntInstallation ai = getAnt();
-        if (!ai.getExists()) {
-        	listener.fatalError(Messages.Ant_ExecutableNotFound(ai.name));
-        	return false;
-        }
-        if(ai==null)
+        if(ai==null) {
+            // Default (ant in PATH)
             args.add(execName);
-        else
+        } else {
+            // Specific installation
+            if (!ai.getExists()) {
+            	listener.fatalError(Messages.Ant_ExecutableNotFound(ai.name));
+            	return false;
+            }
             args.add(ai.getExecutable(launcher));
-
+        }
 
         FilePath buildFilePath = buildFilePath(proj.getModuleRoot());