[XBJAPI-274] Changed an error message when the remote device is not discovered in some examples.

https://jira.digi.com/browse/XBJAPI-274
Signed-off-by: Ruben Moral <Ruben.Moral@digi.com>
Fixed some minor errors.

Signed-off-by: Ruben Moral <Ruben.Moral@digi.com>