Quote Originally Posted by InsaneJ View Post
The screenshot I posted was an example. It was taken on my PC, not on yours

The screenshot you posted shows you are trying to connect using McMultipart. This mod can often be found in the Minecraft\mods\1.7.10 directory
If you delete all the mods that use McMultipart and the 1.7.10 directory, you may be able to join.

YaY
I found and deleted it.
I'm able to join!
Thank you very much for your help!
Sorry, for my English, I'm not good in this language...