I am using the Dreamweaver CC built in SVN 1.6.9 version and it is not working either. Says it cannot connect. I verified the settings from CS6, where it works just fine.
You will need to convert the MXP to a ZXP in the old Extension Manager under Tools -> Convert MXP Extension to ZXP.
I've got the same situation as billp09776 discriped it. Is there any chance to fix this when I don't use the Subweaver extension, or a higher SVN version?
I found a article that says I need to install the "Deprecated Server Support Extension", but this doesn't work?!