DaemonUmbra

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

1.7 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

Please provide debug.log using one of the paste sites listed in my signature below

Client-sided commands don't exist right now because of the way Mojang's new command system is designed.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support. (Pssssst: Read what kind of exception it is and google it)

You're asking why Forge doesn't support you just browsing and screwing with any piece of JSON data that Forge might not even know about?

Yes

Yes, and it shows you have Biomes'O'Plentry installed twice for two different Minecraft versions, as well as sourced from illegal repost sites

Getting debug.log has nothing to do with running the game unless you're trying to generate the file again. Locate your Game Directory (%AppData%/.minecraft, by default) and look in the logs folder, you should see a file called debug.log (or just debug if you have Windows set to hide file extensions)

Can you provide debug.log?

Can you provide debug.log, a video, and your system details/specs please

Can you provide debug.log?

Please keep this forum in English.

1.10 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

1.8 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

By "non-premium" I assume you mean pirate server. Which makes me not want to help.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

1.7 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

Please reproduce the issue and provide debug.log, we need to see the game starting and the world loading up in debug.log (Note that if you haven't enabled Windows Explorer showing file extensions it will appear to just be "debug")