Index: src/main/java/org/jgroups/protocols/pbcast/NAKACK.java
===================================================================
--- src/main/java/org/jgroups/protocols/pbcast/NAKACK.java	(revision 8214)
+++ src/main/java/org/jgroups/protocols/pbcast/NAKACK.java	(working copy)
@@ -740,6 +740,12 @@
 
         long msg_id;
         NakReceiverWindow win=xmit_table.get(local_addr);
+        if (win == null) {
+            win=createNakReceiverWindow(local_addr, INITIAL_SEQNO, 0);
+            xmit_table.put(local_addr, win);
+            if(log.isErrorEnabled())
+                log.error("receive window for " + local_addr + " was null");
+        }
         msg.setSrc(local_addr); // this needs to be done so we can check whether the message sender is the local_addr
 
         seqno_lock.lock();
@@ -896,7 +902,13 @@
             if(log.isErrorEnabled()) {
                 StringBuffer sb=new StringBuffer();
                 sb.append("(requester=").append(xmit_requester).append(", local_addr=").append(this.local_addr);
-                sb.append(") ").append(original_sender).append(" not found in retransmission table: ").append(printMessages());
+                sb.append(") ").append(original_sender).append(" not found in retransmission table: ");
+                
+                // don't add table unless tracing
+                if (log.isTraceEnabled()) {
+                	sb.append(printMessages());
+                }
+                
                 if(print_stability_history_on_failed_xmit) {
                     sb.append(" (stability history:\n").append(printStabilityHistory());
                 }
@@ -911,7 +923,13 @@
                     StringBuffer sb=new StringBuffer();
                     sb.append("(requester=").append(xmit_requester).append(", local_addr=").append(this.local_addr);
                     sb.append(") message ").append(original_sender).append("::").append(i);
-                    sb.append(" not found in retransmission table of ").append(printMessages());
+                    sb.append(" not found in retransmission table");
+                    
+                    // don't add table unless tracing
+                    if (log.isTraceEnabled()) {
+                    		sb.append(" of ").append(printMessages());
+                    }
+                    
                     if(print_stability_history_on_failed_xmit) {
                         sb.append(" (stability history:\n").append(printStabilityHistory());
                     }