This actually looks like a bug with the stratum reconnect code in cgminer since it's happening shortly after btcguild is issuing a reconnect (i.e. change address request), and is coincidental that it's happening for you with the nanofury. Unfortunately I don't have the time to debug and fix this at the moment so a workaround would be to use the redirection address you see in your logs directly instead of the standard btcguild pool address (or a different pool). I've just pushed some generic changes to git which might help this but I don't imagine it will be enough.
No problem
And yes, changing to the redirect address work, less error now. Thanks ck & happy holiday