Comment #2 on issue 59 by danports: Better exception message when trying to
access a property of a session that no longer exists
http://code.google.com/p/cassia/issues/detail?id=59
You'll most often see this exception when you're attempting to access a
property of a session that no longer exists. Given that you're running some
logic on session logoff (based on your stack trace), this result is not
uncommon. The solution would be for you to catch the Win32Exception that is
thrown and handle it appropriately.
It would be better if the library threw an exception with a more specific
error message though.