I think you just made a typo on the first line. You also don't need a group file if you aren't using one.
Code:
AuthUserFile /misc/secure/my.htpasswd
AuthName "Member Files"
AuthType Basic
<Limit GET>
require valid-user
</Limit>
I forgot to say that you will also need to restart apache after moding the config.
/etc/init.d/httpd restart
It doesn't matter about the depth down he directory structure - apache will inherit permissions from the parent directory.