I have also had this problem with MultiMC. Direwolf would work fine until I entered a server IP. Now all it does is crash as soon as I click on Multiplayer. Heres the error I got:
#
# A fatal error has been detected by the Java Runtime Environment:
#
# EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x0000000180008330, pid=8604, tid=8740
#
# JRE version: 7.0_11-b21
# Java VM: Java HotSpot(TM) 64-Bit Server VM (23.6-b04 mixed mode windows-amd64 compressed oops)
# Problematic frame:
# C [BfLLR.dll+0x8330]
#
# Failed to write core dump. Minidumps are not enabled by default on client versions of Windows
#
# If you would like to submit a bug report, please visit:
# http://bugreport.sun.com/bugreport/crash.jsp
# The crash happened outside the Java Virtual Machine in native code.
# See problematic frame for where to report the bug.
I couldnt post anything else becuase it was over 10000 characters. If anyone could identify the problem that would be helpful! I am also using Java 7, 64 bit windows 7, valkyrie cz-17, Nvidia GeForce 670x
#
# A fatal error has been detected by the Java Runtime Environment:
#
# EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x0000000180008330, pid=8604, tid=8740
#
# JRE version: 7.0_11-b21
# Java VM: Java HotSpot(TM) 64-Bit Server VM (23.6-b04 mixed mode windows-amd64 compressed oops)
# Problematic frame:
# C [BfLLR.dll+0x8330]
#
# Failed to write core dump. Minidumps are not enabled by default on client versions of Windows
#
# If you would like to submit a bug report, please visit:
# http://bugreport.sun.com/bugreport/crash.jsp
# The crash happened outside the Java Virtual Machine in native code.
# See problematic frame for where to report the bug.
I couldnt post anything else becuase it was over 10000 characters. If anyone could identify the problem that would be helpful! I am also using Java 7, 64 bit windows 7, valkyrie cz-17, Nvidia GeForce 670x