Seems like pyssh (which is very old AFAIK) uses signal. Looks like you're creating the SSHController instance (which uses pyssh) not in the main thread, and Python won't allow you to place signal handlers outside the main thread.
You can probably move the SSHContorller creation to the main thread, or maybe try using a newer library (such as http://www.lag.net/paramiko/) -- http://mail.python.org/mailman/listinfo/python-list
