Hi again,
Deleting the WinFileCache as suggested doesn't solve the problem for me. I've also tried forcing Dreamweaver to regenerate its Configuration folder and then re-enabling just the CSS Sculptor extension. Product versions are as follows.
CSS Menu Writer 2.0.2
CSS Sculptor 2.0.4
Site Assist Pro 1.0.6
IE 8.0.6001.18813
Firefox 3.5.2
Google Chrome 3.0.195.10 (often the default browser)
I will keep trying different things here. Any further suggestions or insights into what could be going on are welcome, of course. Thanks.