diff --git a/OpenSim.RegionServer/SimClient.cs b/OpenSim.RegionServer/SimClient.cs
index e4c445bd62..d716bd6cc2 100644
--- a/OpenSim.RegionServer/SimClient.cs
+++ b/OpenSim.RegionServer/SimClient.cs
@@ -731,7 +731,17 @@ namespace OpenSim
                     {
                         if (!NeedAck.ContainsKey(Pack.Header.Sequence))
                         {
-                            NeedAck.Add(Pack.Header.Sequence, Pack);
+                            try
+                            {
+                                NeedAck.Add(Pack.Header.Sequence, Pack);
+                            }
+                            catch (Exception e)
+                            {
+                                // Ignore
+                                // Seems to throw a exception here occasionally
+                                // of 'duplicate key' despite being locked.
+                                // !?!?!?
+                            }
                         }
                         else
                         {
diff --git a/OpenSim.RegionServer/world/AvatarUpdate.cs b/OpenSim.RegionServer/world/AvatarUpdate.cs
index 6c0ace774d..34d032c1d4 100644
--- a/OpenSim.RegionServer/world/AvatarUpdate.cs
+++ b/OpenSim.RegionServer/world/AvatarUpdate.cs
@@ -10,6 +10,12 @@ namespace OpenSim.world
     {
         public override void update()
         {
+            if (this._physActor == null)
+            {
+                //HACKHACK: Note to work out why this entity does not have a physics actor
+                //          and prehaps create one.
+                return;
+            }
             libsecondlife.LLVector3 pos2 = new LLVector3(this._physActor.Position.X, this._physActor.Position.Y, this._physActor.Position.Z);
             if (this.updateflag)
             {