Heya

I can see you're making real progress in understanding the beast.

1 - gui\OpenDungeons.layout - line 79 : <Property name="FrameEnabled" value="False" /> => This property doesn't exists for this control. I guess it is a wrong copy/paste since same lines are near.
That one might be my fault. I'll take care of removing the line if you want.
2 - materials\scripts\Refl.material - line 13 : texture Envmap_metal2B.png => This texture doesn't exists. However, there is one named texture Envmap_metal2.png so I don't know if it is the right one or if it is missing
No clue either. Danimal? Elvano?
3 - File Insect_low.003.skeleton is missing. There is no one with a similar name so maybe a forgotten model ?
The model files (.mesh) can invoke any named skeleton file and any named material file to texture them. For instance, the Dojo.mesh file is invoking the Treasury.material file.
To know whether something is missing here, we'd need to know which model file requested the skeleton. Does the log tell it?
Concerning the pause, I cannot use the client/server mecanism as I expected because it doesn't work as I guessed. In fact, I thought that the server was used as a controler to validate games events but as far as I have seen, the events are validated by the client and the server is only used for notification purposes.
It's true certain client parts of the code are validating updates on game state, not asking the server to do those for it. And that's exactly what's wrong, a few exceptions apart, IMHO.
One part of the multiplayer support work is to make sure the client never updates the game state itself, but rather ask the server to do so, so that we can make sure the server notifies every clients about the update. There might be exceptions where, for instance, the client will want to send a render request right away along with notifying the server, to make things a bit quicker, but I still do think it should be rare.
The Editor mode isn't concerned by that part, of course.
BTW, I have tried to implement a pause by stubbing the frame start function within the ODFrameListener when pause is pressed. It works (for the simple cases I have tested - need to be checked with battles) but I will try to display some popup.
Ah, just in case, you should make sure only the client which is hosting can do that.
Concerning the crash when we start another game, I have seen that it is due to Creature Objects that are deleted but still used in the renderer thread. I keep digging.
Ah yes, must be what oln said in the corresponding issue in the tracker. Note that the game updates should be stopped as soon as you quit the game (when pressing escape for now, and later after pushing yes in a confirm dialog.). Maybe working on this could help?
Keep it up!

Best regards,