larsgerrits

I don't see anything related to tooltips, mass or any other information in your ItemElement class. Are you sure you pushed your latest changes to GitHub?

1.7.10 is no longer supported on this forum. Update.

If updating Optifine doesn't work, remove it. It causes more issues than it solves.

Not always true. There are mod developers who put their mod on the Minecraft Forums, or even on their own website. Just make sure you don't download from any fake hosting sites (ckeck http://stopmodreposts.org/). @OP, read up on this: http://pixelmonmod.com/. There won't be any more releases of Pixelmon, so when you see a website releasing a newer version, it's probably fake.

Read. Remove this and Optifine as well. They are coremods and are known to mess things up.

It's a library which is required to be installed for DecoCraft to run. Try installing it, a quick search online revealed the same issue with PTRLib missing.

Cracked launchers are illegal, and you'll probably get banned for using one.

Make sure you have the same mods on both the client and the server (excluding side-only mods).

Post the full logs (logs/latest.log in your game directory). Why do you say this? Both the client and the server logs don't mention Thaumcraft anywhere.

This is not an issue with CraftStudio. He's using a mod (DecoCraft2) which requires another mod (PTRLib) to work. He doesn't have that installed, so it crashes. Installing PTRLib should fix this.

Do you have DecoCraft2 installed? And do you have PTRLib installed with it?

Don't! Coremods should never be used. I think you can do this by making your own world type and removing the other ones, making yours the only one available.

Probably not. You should never touch IDs.

IIRC, ItemStack#getDisplayName returns the custom name if the stack has one. What else are you trying to do?

Post the FML log (logs/fml-client-latest.log in your game directory).

Use Java 8.

This is not by any chance a tutorial. This is mostly copy-paste from the existing Forge docs intro (which is perfectly fine for people new to modding), and gave code which users can copy-paste into their files without learning anything, resulting in the same code as the example source. Also, the CommonProxy system doesn't make sense. Read Code Style, issue #1. Your proxies shouldn't have code to distinguish the dedicated server from the integrated server. Almost all logic should be done on both servers, not just on one of them. That'll cause issues on the other server.

Then you're doing it wrong.

1) Use Java 8, not Java 9. 2) 1.7.10 is no longer supported on this forum. Update.

Don't. 1.7.10 is no longer supported on this forum. Take the hint. Just use an available launcher.

The Twilight Forest and Biomes O' Plenty mod uses ATs to make those variables public in BiomeProvider: Twilight Forest AT and Biomes O' Plenty AT.

If you look closely, you can see that the I18n.setLocale method only gets called from the LanguageManager constructor. So yes, that means they are the same.

1) Your code shows you're not using Forge for MC 1.7. 2) 1.7.10 and lower are not supported on this forum anymore. You should update.

1) This thread is a year old. Don't post in it. 2) Using a cracked launcher can get you banned on here. Just buy the game.