Having similar problem
Running: MacBook Pro 2.33 GHz Intel Core 2 Duo, OS X 10.5.8, Dreamweaver CS4 10.0.0 Build 4117, SiteAssist 3.2.3
Just installed SiteAssist again after upgrading from CS2 to CS4. Now whenever I use SiteAssist it creates the site successfully and uses the right color scheme. All of the specified pages are built. However, the following errors occur:
1. The navigation CSS file is built, but is blank, so the menus are not rendering properly. It does not matter what type of navigation is chosen.
2. The sitemap is undefined.
To troubleshoot I have uninstalled and reinstalled the extension, deleted the cache file and have created a brand new site to run the wizard.