diff -ur ns-3.7/src/internet-stack/ipv4-l3-protocol.cc ns-3-804/src/internet-stack/ipv4-l3-protocol.cc
--- ns-3.7/src/internet-stack/ipv4-l3-protocol.cc	2010-01-28 15:17:45.000000000 -0800
+++ ns-3-804/src/internet-stack/ipv4-l3-protocol.cc	2010-02-03 08:29:13.000000000 -0800
@@ -603,7 +603,15 @@
   Socket::SocketErrno errno_; 
   Ptr<NetDevice> oif (0); // unused for now
   ipHeader = BuildHeader (source, destination, protocol, packet->GetSize (), ttl, mayFragment);
-  Ptr<Ipv4Route> newRoute = m_routingProtocol->RouteOutput (packet, ipHeader, oif, errno_);
+  Ptr<Ipv4Route> newRoute;
+  if (m_routingProtocol != 0)
+    {
+      newRoute = m_routingProtocol->RouteOutput (packet, ipHeader, oif, errno_);
+    }
+  else
+    {
+      NS_LOG_ERROR ("Ipv4L3Protocol::Send: m_routingProtocol == 0");
+    }
   if (newRoute)
     {
       int32_t interface = GetInterfaceForDevice (newRoute->GetOutputDevice ());
diff -ur ns-3.7/src/internet-stack/tcp-l4-protocol.cc ns-3-804/src/internet-stack/tcp-l4-protocol.cc
--- ns-3.7/src/internet-stack/tcp-l4-protocol.cc	2010-01-28 15:17:45.000000000 -0800
+++ ns-3-804/src/internet-stack/tcp-l4-protocol.cc	2010-02-03 08:15:47.000000000 -0800
@@ -584,7 +584,15 @@
       Socket::SocketErrno errno_;
       Ptr<Ipv4Route> route;
       Ptr<NetDevice> oif (0); //specify non-zero if bound to a source address
-      route = ipv4->GetRoutingProtocol ()->RouteOutput (packet, header, oif, errno_);
+      if (ipv4->GetRoutingProtocol () != 0)
+        {
+          route = ipv4->GetRoutingProtocol ()->RouteOutput (packet, header, oif, errno_);
+        }
+      else
+        {
+          NS_LOG_ERROR ("No IPV4 Routing Protocol");
+          route = 0;
+        }
       ipv4->Send (packet, saddr, daddr, PROT_NUMBER, route);
     }
 }
@@ -623,7 +631,15 @@
       header.SetProtocol (PROT_NUMBER);
       Socket::SocketErrno errno_;
       Ptr<Ipv4Route> route;
-      route = ipv4->GetRoutingProtocol ()->RouteOutput (packet, header, oif, errno_);
+      if (ipv4->GetRoutingProtocol () != 0)
+        {
+          route = ipv4->GetRoutingProtocol ()->RouteOutput (packet, header, oif, errno_);
+        }
+      else
+        {
+          NS_LOG_ERROR ("No IPV4 Routing Protocol");
+          route = 0;
+        }
       ipv4->Send (packet, saddr, daddr, PROT_NUMBER, route);
     }
   else
diff -ur ns-3.7/src/internet-stack/tcp-socket-impl.cc ns-3-804/src/internet-stack/tcp-socket-impl.cc
--- ns-3.7/src/internet-stack/tcp-socket-impl.cc	2010-01-28 15:17:45.000000000 -0800
+++ ns-3-804/src/internet-stack/tcp-socket-impl.cc	2010-02-03 10:15:03.000000000 -0800
@@ -1132,6 +1132,11 @@
     {
       return false; // No data exists
     }
+  if (m_endPoint == 0)
+    {
+      NS_LOG_INFO ("TcpSocketImpl::SendPendingData: No endpoint; m_shutdownSend=" << m_shutdownSend);
+      return false; // Is this the right way to handle this condition?
+    }
   uint32_t nPacketsSent = 0;
   while (m_pendingData->SizeFromSeq (m_firstPendingSequence, m_nextTxSequence))
     {
@@ -1181,7 +1186,7 @@
       if (m_shutdownSend)
         {
           m_errno = ERROR_SHUTDOWN;
-          return -1;
+          return false;
         }