--- C:/src/apache-activemq-4.1.1/src/activemq-core/src/main/java/org/apache/activemq/thread/Scheduler.java	Fri Mar 23 13:39:46 2007
+++ C:/src/apache-activemq-4.1.1-local/src/activemq-core/src/main/java/org/apache/activemq/thread/Scheduler.java	Tue Apr 24 16:52:37 2007
@@ -19,6 +19,7 @@
 
 import java.util.HashMap;
 
+import edu.emory.mathcs.backport.java.util.concurrent.RunnableScheduledFuture;
 import edu.emory.mathcs.backport.java.util.concurrent.ScheduledFuture;
 import edu.emory.mathcs.backport.java.util.concurrent.ScheduledThreadPoolExecutor;
 import edu.emory.mathcs.backport.java.util.concurrent.ThreadFactory;
@@ -52,7 +53,8 @@
         ScheduledFuture ticket = (ScheduledFuture) clockTickets.remove(task);
         if( ticket!=null ) {
             ticket.cancel(false);
-        	clockDaemon.remove(task);
+            if (ticket instanceof RunnableScheduledFuture)
+                clockDaemon.remove((RunnableScheduledFuture) ticket);
         }
     }