For General Information, I received a reply from Crashplan support indicating "headless" support is not officially supported. which basically means even though they have directions on the site for setting up a headless configuration, if it doesn't work you're on your own.
Using the instructions posted at support.crashplan.com/doku.php/how_to/co...re_a_headless_client
as a starting point, I was finally able to get the service running after opening TCP ports 4242, 4243, and 4283.
I then opened a winding in Putty and used "ssh -L 4283:localhost:4243 firstname.lastname@example.org
I reopened the GUI client in Windows, and everything seems to be working. I will post a follow-up if there are additional issues.