Проблема с майнкрафт альфа

При попытке загрузить мир на верисии aplha 1.2.6 выдаёт эту ошибку, не знаю что делать:    Minecraft has crashed!      

      ----------------------      

Minecraft has stopped running because it encountered a problem.

If you wish to report this, please copy this entire text and email it to support@mojang.com.

Please include a description of what you did when the error occured.

--- BEGIN ERROR REPORT a1dce528 --------

Generated 03.01.26 22:21

Minecraft: Minecraft Alpha v1.2.6

OS: Windows 10 (amd64) version 10.0

Java: 1.8.0_51, Oracle Corporation

VM: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation

LWJGL: 2.9.0

OpenGL: Radeon RX550/550 Series version 4.6.0 Compatibility Profile Context 22.11.2.221130, ATI Technologies Inc.

java.lang.NullPointerException

at fp.b(SourceFile:67)

at af.a(SourceFile:131)

at nl.a(SourceFile:311)

at nl.a(SourceFile:136)

at kb.b(SourceFile:315)

at net.minecraft.client.Minecraft.run(SourceFile:622)

at java.lang.Thread.run(Thread.java:745)

--- END ERROR REPORT 56253ec0 ----------