LolManKuba wrote:Um how is my world lost? Because 0.4 is unstable so this could be one of the errors with the world part of 0.4
The world isn't lost you just won't be able to load it in older versions of Minetest.
A few things changed in the code that made the new world data stuff work differently meaning that because the world was created in 0.4 of Minetest you will need 0.4+ to play on it, even if the world was originally created in 0.3 if you have since loaded it in 0.4 it will have been converted to use the new 0.4 map format so it will no longer work in 0.3.
So basically if you want to continue playing that world you will have to stick with version 0.4 (or higher) otherwise if you do want to use an older version of Minetest (i.e. 0.3.1) you will need to start a new world.