[stunnel-users] Unable to open "/dev/cryptonet"

hello, when i run stunnel4.x under linux it gaves statment Unable to open "/dev/cryptonet" but it run normal .. what this error mean ? does it means stunnel is running but not encrypting ? and is there any problem running stunnel without "/dev/cryptonet ? secand question i have stunnel4.x running with verify 3 option can my isp read data between me and the other host .. if i am transmiting data through stunnel ? thanks.