--- a/src/wifi/model/regular-wifi-mac.cc	Wed May 22 17:22:49 2013 -0700
+++ b/src/wifi/model/regular-wifi-mac.cc	Wed May 22 17:58:58 2013 -0700
@@ -512,10 +512,13 @@
 
             default:
               NS_FATAL_ERROR ("Unsupported Action field in Block Ack Action frame");
+              return;
             }
 
+
         default:
           NS_FATAL_ERROR ("Unsupported Action frame received");
+          return;
         }
     }
   NS_FATAL_ERROR ("Don't know how to handle frame (type=" << hdr->GetType ());