ex_handle_except encountered exception C0000005 - Server terminating

Can somebody tell me what has caused the error based upon this stack output.

Our version is:

Microsoft SQL Server 2008 R2 (SP1) - 10.50.2500.0 (X64)   Jun 17 2011 00:54:03   Copyright (c) Microsoft Corporation  Enterprise Edition (64-bit) on Windows NT 5.2 <X64> (Build 3790: Service Pack 2) 

Call Site
ntdll!NtWaitForSingleObject
kernel32!WaitForSingleObjectEx
sqlservr!CDmpDump::DumpInternal
sqlservr!CDmpDump::DumpFilter
sqlservr!CDmpDump::Dump
msvcr80!_C_specific_handler
ntdll!RtlpExecuteHandlerForException
ntdll!RtlDispatchException
ntdll!RtlRaiseException
kernel32!RaiseException
sqlservr!CDmpDump::Dump
sqlservr!SQLDumperLibraryInvoke
sqlservr!CImageHelper::DoMiniDump
sqlservr!stackTrace
sqlservr!stackTraceCallBack
sqlservr!ex_handle_except
kernel32!UnhandledExceptionFilter
kernel32!BaseThreadStart
ntdll!_C_specific_handler
ntdll!RtlpExecuteHandlerForException
ntdll!RtlDispatchException
ntdll!KiUserExceptionDispatch
winhttp!RemoveFromSerializedList
winhttp!InternetDestroyThreadInfo
winhttp!DllMain
winhttp!DllMainCRTStartup
ntdll!LdrShutdownThread
kernel32!ExitThread
msvcr80!endthreadex
msvcr80!endthreadex
msvcr80!endthreadex
kernel32!BaseThreadStart