For those who want to play single player with the SMXui Mod, I did the following to get rid of the console errors and Player window stuck on-screen:
Always back up any files modified so you can revert the changes if needed.
Find the 7 Days to Die Mods folder containing the SMXui mod (if you are here, you should know where you extracted the mod).
Browse to .\Mods\SMXui\Config\XUi and edit the windows.xml file (after making a backup copy).
Comment out the following sections in the XML (using <!-- to start the commented section and --> to end it):
Under the section labelled <!-- // SMX // Window Paging Header --> comment out line 148 that starts with <button name="Players". Also comment out line 149 beneath that starting with <label name="Players"
Under the section labelled <!-- // SMX // Players Window --> comment the entire section ranging from line 874 that starts with <remove xpath="/windows/window[@name='players']" /> down to, and including, line 918 that starts with </append>
Save the file and start your 7 Days to Die game.
Starting/continuing any game should now be possible without the errors and orphaned Players window. This may not be desirable in multiplayer games since this effectively disables the Player window, but it will get you into the game until the mod author has a chance to figure out what TFP hosed up.
I hope this helps. Sorry I didn't have time to insert screenshots and pretty things up, but you's smart peeps.
