Hi - I've just downloaded the newest version, doing a test install in my local machine (Vista x64 / XAMPP for Windows Version 1.7.1 - which runs Joomla fine) and I get the exact same problem.
The current permission come up as "777 Non-writable" for all folders with desired level as "777 Writable".
Seems odd to me as I thought 777 = writable, so why the error? Anyway, I tried messing around with permissions on the folders requested, but nothing changes its.
The impact of this problem is that installation cannot take place (next page appears with error).
Seems odd as I got it working with v6.1.4
Update - I guess this ticket is for the issue, so its confirmation that its a bug? http://www.boonex.com/trac/dolphin/ticket/653
Guess I'll wait for v6.1.6 then.