Error while running event show-fluid-temperature-in-pipe-and-tank-gui::on_nth_tick(10)
show-fluid-temperature-in-pipe-and-tank-gui/control.lua:170: attempt to index field 'fluidbox' (a nil value)
stack traceback:
show-fluid-temperature-in-pipe-and-tank-gui/control.lua:170: in function <show-fluid-temperature-in-pipe-and-tank-gui/control.lua:164>

Can you provide more context? What entity did you try to open and from what mod is it?

Thanks for the report, I've fixed a bug in 1.0.3, if you were playing in multiplayer (at some point in that game), that should be it.

After the update, it crashed under the same conditions.

Error while running event show-fluid-temperature-in-pipe-and-tank-gui::on_nth_tick(10)
show-fluid-temperature-in-pipe-and-tank-gui/control.lua:170: attempt to index field 'fluidbox' (a nil value)
stack traceback:
show-fluid-temperature-in-pipe-and-tank-gui/control.lua:170: in function <show-fluid-temperature-in-pipe-and-tank-gui/control.lua:164>

https://mods.factorio.com/mod/item-network-sa?from=search

The game crashed when I tried to open this mod's GUI.

Thanks, will look into it more when able. I'd guess that mod has some custom GUI which causes my mod to break

Yep, its fixed in 1.0.4