.htaccess password protection breaks nested wordpress blogs

Hi, I have three WordPress 2.5.1 blogs running on the same domain, and for the most part they work great. They are:

https://cantonbecker.com/ (installed in root)
https://cantonbecker.com/yellowish-macbook-display/

and a 3rd WP blog, also installed in its own directory just like yellowish-macbook-display

However the 3rd WP blog is password protected using .htaccess

It was working great until I installed a blog at the root level of the whole domain. Now, I get a 404 when I try to access the 3rd WP blog.

If I disable the .htaccess password protection, the 3rd blog comes back to life.

Any ideas on why .htaccess password protection is breaking on a “nested” wordpress blog installation?

BTW all 3 blogs use date/name URL rewriting mods.