Constant crashes in the Nether (Multiplayer as far as I know)

What I expected to happen was...:
Just be a simple little trip to the Nether, no crashes or unexpected quits.

What actually happened was...:
Game quits unexpectedly, leaving a hs_err_pid crash report. Sometimes it will say that Java Binary has stopped working.

Steps to Reproduce:
Not possible to reproduce unless a specific computer is found.

A crash report known as hs_err_pid3888:

#
# A fatal error has been detected by the Java Runtime Environment:
#
#  Internal Error (os_windows_x86.cpp:149), pid=3888, tid=6516
#  guarantee(result == EXCEPTION_CONTINUE_EXECUTION) failed: Unexpected result from topLevelExceptionFilter
#
# JRE version: 6.0_30-b12
# Java VM: Java HotSpot(TM) 64-Bit Server VM (20.5-b03 mixed mode windows-amd64 compressed oops)
# If you would like to submit a bug report, please visit:
#   http://java.sun.com/webapps/bugreport/crash.jsp
#

---------------  T H R E A D  ---------------

Current thread (0x00000000079ca800):  JavaThread "Minecraft main thread" daemon [_thread_in_Java, id=6516, stack(0x000000000b3d0000,0x000000000b4d0000)]

Stack: [0x000000000b3d0000,0x000000000b4d0000]
[error occurred during error reporting (printing stack bounds), id 0xc0000005]


---------------  P R O C E S S  ---------------

Java Threads: ( => current thread )
  0x0000000007b8a800 JavaThread "Client write thread" daemon [_thread_blocked, id=6956, stack(0x0000000008790000,0x0000000008890000)]
  0x00000000079ce000 JavaThread "Client read thread" daemon [_thread_blocked, id=6464, stack(0x0000000002870000,0x0000000002970000)]
  0x00000000079d0000 JavaThread "Thread-24" daemon [_thread_in_native, id=2156, stack(0x0000000015ce0000,0x0000000015de0000)]
  0x00000000079ce800 JavaThread "Thread-16" daemon [_thread_in_native, id=7088, stack(0x0000000015be0000,0x0000000015ce0000)]
  0x00000000079cb800 JavaThread "Thread-13" daemon [_thread_blocked, id=4060, stack(0x00000000146e0000,0x00000000147e0000)]
  0x00000000079cb000 JavaThread "Thread-12" daemon [_thread_blocked, id=5380, stack(0x00000000145e0000,0x00000000146e0000)]
=>0x00000000079ca800 JavaThread "Minecraft main thread" daemon [_thread_in_Java, id=6516, stack(0x000000000b3d0000,0x000000000b4d0000)]
  0x00000000079c9800 JavaThread "Timer hack thread" daemon [_thread_blocked, id=5036, stack(0x000000000b2d0000,0x000000000b3d0000)]
  0x00000000079c9000 JavaThread "Snooper Timer" daemon [_thread_blocked, id=6964, stack(0x000000000b150000,0x000000000b250000)]
  0x00000000079e5000 JavaThread "TimerQueue" daemon [_thread_blocked, id=5664, stack(0x000000000abb0000,0x000000000acb0000)]
  0x0000000007632800 JavaThread "Keep-Alive-Timer" daemon [_thread_blocked, id=7148, stack(0x0000000009ad0000,0x0000000009bd0000)]
  0x00000000005cb800 JavaThread "DestroyJavaVM" [_thread_blocked, id=3780, stack(0x0000000002b20000,0x0000000002c20000)]
  0x0000000007510000 JavaThread "AWT-EventQueue-0" [_thread_blocked, id=5704, stack(0x0000000008ba0000,0x0000000008ca0000)]
  0x0000000006cb8800 JavaThread "AWT-Windows" daemon [_thread_in_native, id=4852, stack(0x0000000008430000,0x0000000008530000)]
  0x0000000006d8d000 JavaThread "AWT-Shutdown" [_thread_blocked, id=4016, stack(0x0000000008330000,0x0000000008430000)]
  0x0000000006d8c800 JavaThread "Java2D Disposer" daemon [_thread_blocked, id=1524, stack(0x00000000081a0000,0x00000000082a0000)]
  0x0000000006c32800 JavaThread "Low Memory Detector" daemon [_thread_blocked, id=5696, stack(0x00000000072c0000,0x00000000073c0000)]
  0x0000000006c2f800 JavaThread "C2 CompilerThread1" daemon [_thread_blocked, id=2216, stack(0x00000000071c0000,0x00000000072c0000)]
  0x0000000006c1d000 JavaThread "C2 CompilerThread0" daemon [_thread_blocked, id=1716, stack(0x00000000070c0000,0x00000000071c0000)]
  0x0000000006c1a000 JavaThread "Attach Listener" daemon [_thread_blocked, id=6384, stack(0x0000000006fc0000,0x00000000070c0000)]
  0x0000000006c15000 JavaThread "Signal Dispatcher" daemon [_thread_blocked, id=4652, stack(0x0000000006ec0000,0x0000000006fc0000)]
  0x0000000006bc5800 JavaThread "Finalizer" daemon [_thread_blocked, id=2516, stack(0x0000000006dc0000,0x0000000006ec0000)]
  0x00000000003f9800 JavaThread "Reference Handler" daemon [_thread_blocked, id=5584, stack(0x0000000006ac0000,0x0000000006bc0000)]

Other Threads:
  0x00000000003f3800 VMThread [stack: 0x00000000069c0000,0x0000000006ac0000] [id=4480]
  0x0000000006c44000 WatcherThread [stack: 0x00000000073c0000,0x00000000074c0000] [id=5900]

VM state:synchronizing (normal execution)

VM Mutex/Monitor currently owned by a thread:  ([mutex/lock_event])
[0x00000000005c9900] Safepoint_lock - owner thread: 0x00000000003f3800
[0x00000000005c9980] Threads_lock - owner thread: 0x00000000003f3800
[0x00000000005c9e80] Heap_lock - owner thread: 0x00000000079ce000

Heap
 PSYoungGen      total 152896K, used 131043K [0x00000000eaab0000, 0x00000000f5550000, 0x0000000100000000)
  eden space 131072K, 99% used [0x00000000eaab0000,0x00000000f2aa8ec0,0x00000000f2ab0000)
  from space 21824K, 0% used [0x00000000f2ab0000,0x00000000f2ab0000,0x00000000f4000000)
  to   space 21824K, 0% used [0x00000000f4000000,0x00000000f4000000,0x00000000f5550000)
 PSOldGen        total 349568K, used 37534K [0x00000000c0000000, 0x00000000d5560000, 0x00000000eaab0000)
  object space 349568K, 10% used [0x00000000c0000000,0x00000000c24a7858,0x00000000d5560000)
 PSPermGen       total 61888K, used 28386K [0x00000000bae00000, 0x00000000bea70000, 0x00000000c0000000)
  object space 61888K, 45% used [0x00000000bae00000,0x00000000bc9b8bd0,0x00000000bea70000)

Code Cache  [0x0000000002c20000, 0x0000000002ef0000, 0x0000000005c20000)
 total_blobs=1466 nmethods=786 adapters=632 free_code_cache=47483584 largest_free_block=11392

Dynamic libraries: