Unfortunately the mod crashes with a LUA error message stream when I select a Hydrogen Furnace from the list in the GUI. It is the mod "Hydrogen Power Systems". Can you please look into it?

The error is "Unknown item name: CW-hydrogen-furnace-3B" followed by a stack traceback.

Thanks for the report. Should be fixed in the latest update

Is your mod designed the way that you have to add every existing item from any mod or else it crashes, or was it a different problem?

The selection gui for assemblers/furnaces gives me the item name, i save the corresponding entity name and when reopening the gui set the button to the stored name. Works fine with vanilla and most mods, but for some mods the item/entity name isn't the same.
So a different problem, all mods should work fine from now on

Great!