Ok, this page: https://boxcryptor.desk.com/customer/portal/articles/667245-what-does-the-%22path-is-too-long%22-error-mean-and-how-can-i-resolve-it- explains the problem pretty well. So I've disabled long file names in boxcryptor so that skydrive will work.
I think this will work, because BC is flagging me periodically on long file name errors. Hopefully that means it is ignoring the affected files, which will run interference for skydrive.
What would be nice would be to silence the BC long file errors. Any file so flagged is not important to me at this point.
Really, this is skydrive's problem, and I have a complaint in with them, but I would like to get this up and running.