Craftland

I have very low amount of ram but craftland runs smoothly then all of a sudden craftland freezes and then about 10 minutes later it finally says it crashed and then my mouse can move but what i see the second before it freezes is that the cpu usage of crafltnad drops to 1-3% and then the ram usage stays the same.
The output on the crash screen is this

###############################      
#   Minecraft has crashed !   #      
###############################      

— BEGIN ERROR REPORT f4b219e6 ——– Generated 9/11/15 7:54 PM

Mod version: 6.4e
Resource Packs: Default;resources;Default (minecraft.jar)
OS: Linux (i386 on x86 OS) version 3.19.0-26-generic
Java: 1.7.0_79, Oracle Corporation
JVM Memory: 1979MB
Texture Memory: Allocated 32.35 MBMB
Tesselator buffers: 8650752 Bytes / 4980736 Bytes
VM: OpenJDK Client VM (mixed mode, sharing), Oracle Corporation
LWJGL: 2.9.0
OpenGL: Mesa DRI Intel(R) 915G x86/MMX/SSE2 version 1.4 Mesa 10.5.9, Intel Open Source Technology Center

Unexpected error
java.lang.Throwable: Forced interruption!

at dtfgdttdfgfgdtbb.run(SourceFile:36)

— END ERROR REPORT cc950f04 ———-

I was swimming up a waterfall thing in the aether because I fell and 1 block from the top I died and my items didn’t go into a tombstone because of the region their and the items fell out of the aether and disappeared.

When you place a 1x1 display case it comes out as a 32x32 display case and when you break it it drops a 32x32 I haven't been able to replicate it with any other sizes