As near as I can tell, I'm doing everything right after meticulously following
http://www.gammon.com.au/mushclient/stunnel.htm
There were a few changes here and there, so I'm not sure if this makes the difference. I had to go to the openssl website and download the version of the file mentioned, which did not contain all the components listed (libssl32.dll, libeay32.dll and openssl.exe), but I figured I'd try anyway.
Launching stunnel after doing all the configuration gave me the following result in the log:
2012.10.19 09:28:09 LOG5[5624:4220]: Reading configuration from file stunnel.conf
2012.10.19 09:28:09 LOG5[5624:4220]: FIPS mode is enabled
2012.10.19 09:28:09 LOG5[5624:4220]: Configuration successful
That looked about as good as I could hope, but MushClient seems unable to connect to 'localhost' on port '5555' as I designated (again following the isntructions blindly):
Unable to connect to "MyMUDStunnel", code = 10061 (Connection refused)
Error occurred during phase: Connecting to world: 127.0.0.1, port 5555
For assistance with connection problems see:
http://www.gammon.com.au/forum/?id=8369
Any guess where my disconnect may lie?
Oh, and I should note that I'm able to connect this SSH thing with PuTTY without a problem.