Firefox 3. Assertion 'KeGetPreviousMode() == UserMode' failed

Assertion 'KeGetPreviousMode() == UserMode' failed at ntoskrnl/ke/i386/usercall.c line 143

KeUserModeCallback ke/i386/usercall.c:143
co_IntCallHookProc ntuser/callback.c:488
co_HOOK_CallHooks ntuser/hook.c:351
IntCallWndProc ntuser/message.c:317
co_IntSendMessageTimeoutSingle ntuser/message.c:1497
co_IntSendMessageTimeout ntuser/message.c:1616
co_IntSendMessage ntuser/message.c:1461
IntSendDestroyMsg ntuser/window.c:296
co_UserFreeWindow ntuser/window.c:403
co_UserDestroyWindow ntuser/window.c:2444
co_DestroyThreadWindows ntuser/window.c:723
Win32kThreadCallback main/dllmain.c:301
PspExitThread ps/kill.c:690
PspTerminateThreadByPointer ps/kill.c:964
NtTerminateProcess ps/kill.c:1188
KiFastCallEntry ke/i386/trap.s:244
ZwTerminateProcess ex/zw.S:2414
KiDispatchException ke/i386/exp.c:1049
CommonDispatchException ke/i386/trap.s:638
RtlDispatchException lib/rtl/i386/except.c:78
KiUserExceptionDispatcher dll/ntdll/dispatch/i386/dispatch.S:199
RtlpExecuteHandler lib/rtl/i386/except_asm.s:163