STOP error (BSOD) aswMonFlt.sys (X64_IP_MISALIGNED_aswMonFlt.sys)

OS: Windows 7 x64 - current (all updates installed)
Avast! Free Antivirus: 5.0.677 with latest AV definition (101227-0)

Problem: while browsing the Web (normal text + JS content), I experienced a STOP error (aka BSOD).
I am not sure if the problem is caused by Avast! or “hardware” (or OS/device driver).
The computer is connected to network via a WiFi NIC with static IP and no IPv6.

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Microsoft (R) Windows Debugger Version 6.12.0002.633 AMD64
Copyright (c) Microsoft Corporation. All rights reserved.

Loading Dump File [C:\Windows\MEMORY.DMP]
Kernel Summary Dump File: Only kernel address space is available

Symbol search path is: srvc:\symbolshttp://msdl.microsoft.com/download/symbols
Executable search path is: c:\windows\minidump
Windows 7 Kernel Version 7600 MP (2 procs) Free x64
Product: WinNt, suite: TerminalServer SingleUserTS
Built by: 7600.16617.amd64fre.win7_gdr.100618-1621
Machine Name:
Kernel base = 0xfffff80002e04000 PsLoadedModuleList = 0xfffff80003041e50
Debug session time: Mon Dec 27 21:39:08.295 2010 (UTC + 8:00)
System Uptime: 4 days 15:52:38.225
Loading Kernel Symbols



Loading User Symbols

Loading unloaded module list


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  •                    Bugcheck Analysis                                    *
    
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Use !analyze -v to get detailed debugging information.

BugCheck 7E, {ffffffffc0000005, fffff88004577210, fffff880047a5a98, fffff880047a5300}

*** ERROR: Module load completed but symbols could not be loaded for aswMonFlt.sys
Probably caused by : hardware ( aswMonFlt+5210 )

Followup: MachineOwner

1: kd> !analyze -v


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  •                    Bugcheck Analysis                                    *
    
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SYSTEM_THREAD_EXCEPTION_NOT_HANDLED (7e)
This is a very common bugcheck. Usually the exception address pinpoints
the driver/function that caused the problem. Always note this address
as well as the link date of the driver/image that contains this address.
Arguments:
Arg1: ffffffffc0000005, The exception code that was not handled
Arg2: fffff88004577210, The address that the exception occurred at
Arg3: fffff880047a5a98, Exception Record Address
Arg4: fffff880047a5300, Context Record Address

Debugging Details:

EXCEPTION_CODE: (NTSTATUS) 0xc0000005 - The instruction at 0x%08lx referenced memory at 0x%08lx. The memory could not be %s.

FAULTING_IP:
aswMonFlt+5210
fffff880`04577210 0000 add byte ptr [rax],al

EXCEPTION_RECORD: fffff880047a5a98 – (.exr 0xfffff880047a5a98)
ExceptionAddress: fffff88004577210 (aswMonFlt+0x0000000000005210)
ExceptionCode: c0000005 (Access violation)
ExceptionFlags: 00000000
NumberParameters: 2
Parameter[0]: 0000000000000001
Parameter[1]: 0000000004384800
Attempt to write to address 0000000004384800

CONTEXT: fffff880047a5300 – (.cxr 0xfffff880047a5300)
rax=0000000004384800 rbx=000003a655dcfb00 rcx=00000000000000b4
rdx=0000000000000000 rsi=fffffa80018e2840 rdi=0000000000000001
rip=fffff88004577210 rsp=fffff880047a5cd0 rbp=0000000000000080
r8=0000000000000000 r9=0000000000000f44 r10=fffff80002e04000
r11=0000000000000000 r12=0000000000000000 r13=fffff88004577528
r14=0000000000000000 r15=fffff880009e8ec0
iopl=0 nv up ei pl nz na po nc
cs=0010 ss=0018 ds=002b es=002b fs=0053 gs=002b efl=00010206
aswMonFlt+0x5210:
fffff88004577210 0000 add byte ptr [rax],al ds:002b:0000000004384800=??
Resetting default scope

DEFAULT_BUCKET_ID: VISTA_DRIVER_FAULT

PROCESS_NAME: System

CURRENT_IRQL: 0

ERROR_CODE: (NTSTATUS) 0xc0000005 - The instruction at 0x%08lx referenced memory at 0x%08lx. The memory could not be %s.

EXCEPTION_PARAMETER1: 0000000000000001

EXCEPTION_PARAMETER2: 0000000004384800

WRITE_ADDRESS: 0000000004384800

FOLLOWUP_IP:
aswMonFlt+5210
fffff880`04577210 0000 add byte ptr [rax],al

BUGCHECK_STR: 0x7E

MISALIGNED_IP:
aswMonFlt+5210
fffff880`04577210 0000 add byte ptr [rax],al

LAST_CONTROL_TRANSFER: from fffff88004577576 to fffff88004577210

STACK_TEXT:
fffff880047a5cd0 fffff88004577576 : 000003a655dcfb00 0000000000000080 fffffa80018e2840 0000000000000001 : aswMonFlt+0x5210
fffff880047a5d10 fffff80003118c06 : 00000000077665d4 fffffffffeced300 fffff880047a5db0 fffffa8003d41640 : aswMonFlt+0x5576
fffff880047a5d40 fffff80002e52c26 : fffff880009e4180 fffffa8003d41640 fffff880009eef40 fffff88001246a90 : nt!PspSystemThreadStartup+0x5a
fffff880047a5d80 0000000000000000 : fffff880047a6000 fffff880047a0000 fffff880047a5a90 0000000000000000 : nt!KxStartSystemThread+0x16

SYMBOL_STACK_INDEX: 0

SYMBOL_NAME: aswMonFlt+5210

FOLLOWUP_NAME: MachineOwner

MODULE_NAME: hardware

IMAGE_NAME: hardware

DEBUG_FLR_IMAGE_TIMESTAMP: 0

STACK_COMMAND: .cxr 0xfffff880047a5300 ; kb

FAILURE_BUCKET_ID: X64_IP_MISALIGNED_aswMonFlt.sys

BUCKET_ID: X64_IP_MISALIGNED_aswMonFlt.sys

Followup: MachineOwner

It’s caused by avast - could you please compress (7z/rar) & upload “C:\Windows\MEMORY.DMP” to our ftp?
instructions are here: http://support.avast.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=18&nav=0

Thanks.