Looks fine to me. Same configuration works in my Windows 7 64 bits. I have no access to Windows Server 2008 R2, but I would expect it to work the same.
What are you securing with stunnel?... Perhaps the service you are securing is starting after stunnel?
From: John Smith <java.dev.mtl@gmail.com>
Date: Mon, 22 Sep 2014 11:09:21 -0400
To: Jose Diaz<josealf@rocketmail.com>
Subject: Re: [stunnel-users] Stunnel as windows service doesn't start on restart.
SERVICE_NAME: stunnel
TYPE : 110 WIN32_OWN_PROCESS (interactive)
START_TYPE : 2 AUTO_START
ERROR_CONTROL : 1 NORMAL
BINARY_PATH_NAME : "C:\Program Files (x86)\stunnel\stunnel.exe" -service -install
LOAD_ORDER_GROUP :
TAG : 0
DISPLAY_NAME : Stunnel SSL wrapper
DEPENDENCIES : TCPIP
SERVICE_START_NAME : LocalSystem