This is a protracted tale.
I installed WP1.5 yesterday, and today while configuring and customizing, I accidentally made several mistakes in trying to get the template stylesheet to be writable. As I wasn't sure about the chmods, I ended up winging it until 766 seemed to work. (Is that correct? Currently I have the files in the directory chmod'ed to 766 and the directory as 755. The codex help document lists both 766 and 666). I then made several mistakes while editing the stylesheet, and decided to delete the whole "default" directory and re-upload it from the fresh copy of WP1.5 I had on my computer.
Now no matter what changes I make to the stylesheet, nothing shows up when I refresh my page. I tried everything from tentative font-color changes to wholescale structural upheavals, and the page stoically remains http://www.idlethink.com/wordpress. The other templates work fine - I removed the image CSS from the index with no problem, and I can mess around with all .php files. But nothing I do to the CSS file makes a difference. I'm familiar enough with CSS to know what I should be changing, but nothing I've done has worked. I've also downloaded other templates and installed them, and editing them is also fine. Basically, I seem to have screwed up the default stylesheet...somehow.
If anyone has any suggestions on how to fix WP1.5's Kubrick, I would be awfully grateful! There's no Kubrick download for WP1.5 on Michael Heilemann's website, and I didn't think that re-uploading the directory would cause so much trouble (at least, I think that's what did it).
Sorry for making this long, and I do apologize in advance if I am being cretinous.