Zenor

Glad to hear that the error is gone. Adding new goods/productions to an existing galaxy will work fine as long as you add them to the end of the index files. Factories store all their production data in the save file so removing or in this case renaming a good/production will cause errors. I would guess that in the process of changing 'Self-Heating Pizza Box' to 'Pizza Box' one of the factories was set to make pizza boxes but it failed to properly setup its list of sold goods, so afterwards whenever it checked whether it had enough space in storage to make another pizza box it would produce that error. The reason I specifically stated to add the new goods/productions to the end of the lua file is because factories save the 'index' of the production, which is its position in productionsindex.lua. I have not tested this out in-game but that would suggest that adding productions to the beginning of that file or even reordering the list of productions could cause problems in pre-existing galaxies. Oh, and to answer an earlier question. A good's level/importance affects how likely it will be chosen as the produced good when spawning a random factory, higher level goods are rarer while more important goods are more common. Also some sectors only spawn factories that produces goods of a certain range of levels, so adding tons of low level goods will not have too great of an effect on the number of factories that spawn producing high level goods. Alas, there are no cookies in Avorion... perhaps that can be fixed...

Has all your testing been in the same galaxy? If so, may I suggest that you try creating a new galaxy and test if spawning the factories in there no longer produces that error? This is based on my somewhat limited understanding of the factories work. Normally I would post a 'brief' explanation of my reasoning along with my suggestion but I do not the time to write it up currently, although if testing in a brand new galaxy does not generate the error then I can post an explanation later on if you wish.