Issues w/permissions on plesk-stat and webstat

[blizz81]

One of our clients is having trouble accessing their webstat page - it prompts for authentication, and nothing (their local user account associated with their plesk account, the local administrator account, etc) seems to be able to access it.

I've assigned permissions to the plesk-stat and webstat directories in IIS to no avail. If I right-click and Browse from the IIS interface, I get prompted for authentication. The plesk-stat site has anon access enabled, and like I said, I manually granted other permissions to local users and still can't access it. Any suggestions?