In the stunnel log I find
2013.08.08 18:27:42 LOG5[40:31]: stunnel 4.56 on x86-pc-msvc-1500 platform
2013.08.08 18:27:42 LOG5[40:31]: Compiled/running with OpenSSL 1.0.1e-fips 11 Feb 2013
2013.08.08 18:27:42 LOG5[40:31]: Threading:WIN32 Sockets:SELECT,IPv6 SSL:ENGINE,OCSP,FIPS
2013.08.08 18:27:42 LOG5[40:31]: Reading configuration from file stunnel.conf
2013.08.08 18:27:42 LOG5[40:31]: FIPS mode is enabled
2013.08.08 18:27:42 LOG5[40:31]: Configuration successful
2013.08.08 18:28:44 LOG5[40:47]: Service [gmail-smtp] accepted connection from 127.0.0.1:43854
2013.08.08 18:28:45 LOG5[40:47]: connect_blocking: connected 74.125.136.108:465
2013.08.08 18:28:45 LOG5[40:47]: Service [gmail-smtp] connected remote server from 192.168.1.10:60142
2013.08.08 18:28:45 LOG3[40:47]: INTERNAL ERROR: s_poll_wait returned 0, but no descriptor is ready
2013.08.08 18:28:45 LOG5[40:47]: Connection reset: 79 byte(s) sent to SSL, 53 byte(s) sent to socket
So stunnel seems to run correctly. In case it is needed I generated a certificate.