I have exactly the same site settings in coda 1.7.4 as I do in coda 2 but when I click the publish arrow in coda 2 it tells me "Set both local and Remote paths in a site to publish your changes". I have already done that but it still is not working. As I said the same settings are in the older version and it works fine and publishes.
Anyone have any of the same problems.
Answer
I contacted Coda support for exactly this issue today... Same as you, after setting up a site with the correct remote and local roots - confirmed because I could connect to both - but still the publish window said "Set both local and Remote paths in a site to publish your changes".
Literally the solution was to close Coda down and re-open it. Apparently this is a known issue, when setting up a new site you have to restart Coda to use the publish functionality.
Just by closing Coda and restarting it the publish function now works for me.