In trying to load modrex, I first disable the authentication hash
check, since rex authentication does not correctly when behind a
router. Then, when I launch the rex viewer, it gets as far as "
realxtend..Connecting to Region..." and then a pop-up error states:

Unfortunately the session for this client on the server has crashed
Any further actions taken will not be processed.

I am including the key parts of the opensim console log where the
crash information appears. I have replaced the actual external IP
with "<external IP>" :
 
.............
21:53:29 - [REXCLIENT]: Confirmed connection from RexPacketServer. This user
can
 use Rex functionalities.
21:53:29 - [VOICECHAT]: New client: 4da740fa-bb57-4dd7-860b-953142f0e37b
21:53:29 - [REXAPR]: Sending user 4da740fa-bb57-4dd7-860b-953142f0e37b
appearanc
e to all users. []
21:53:29 - [REXAPR]: Skipping blank URL on user...
21:53:29 - [REXAPR]: Sending all appearances to user
4da740fa-bb57-4dd7-860b-953
142f0e37b.
21:53:29 - [REXCLIENT]: Recieved Rex Appearance
21:53:29 - [REXAPR]: Sending user 4da740fa-bb57-4dd7-860b-953142f0e37b
appearanc
e to all users. [http://<external
IP>:10000/avatar/4da740fabb574dd7860b953142f0
e37b]
21:53:29 - [CLIENT]: Entered main packet processing loop for Meta Phorz
<metapho
rz@<external IP>:10001> in Metaphorz
21:53:29 - [SCENE]: Upgrading child to root agent for Meta Phorz
<metaphorz@<external IP>:10001> in Metaphorz
21:53:30 - [PRESENCE]: Failed to notify message server of agent location for
4da
740fa-bb57-4dd7-860b-953142f0e37b
21:53:30 - [LOCAL INVENTORY SERVICE]: Requesting inventory for user
4da740fa-bb5
7-4dd7-860b-953142f0e37b
21:53:30 - [LOCAL INVENTORY SERVICE]: Received inventory response for user
4da74
0fa-bb57-4dd7-860b-953142f0e37b containing 15 folders and 0 items
21:53:30 - [WORLD MAP]: Starting remote MapItem request thread
21:53:30 - [CLIENT]: Client thread for Meta Phorz <metaphorz@<external
IP>:10001> 4da740fa-bb57-4dd7-860b-953142f0e37b crashed.  Logging them
out.
   at OpenSim.Framework.PacketPool.ReturnDataBlock[T]:(T block)
21:53:30 - [CLIENT]: Got a logout request for Meta Phorz
<metaphorz@<external IP>:10001> in Metaphorz
21:53:30 - [CLIENT]: Close has been called with shutdownCircuit = False for
Meta
 Phorz <metaphorz@<external IP>:10001> attached to scene Metaphorz
21:53:30 - [SCENE]: Removing root agent 4da740fa-bb57-4dd7-860b-953142f0e37b
fro
m region Metaphorz
21:53:30 - [USER DB]: Syncing useragent database: 2 agents stored
21:53:30 - [EVENTQUEUE]: Closed client 4da740fa-bb57-4dd7-860b-953142f0e37b in
r
egion Metaphorz
21:53:33 - [PRESENCE]: Failed to notify message server of agent leaving for
4da7
40fa-bb57-4dd7-860b-953142f0e37b
Region (Metaphorz) #