Authentication and Large Files

All,

I've recently run into the large file download problem.  I've made all of the recommended Metafile.XML changes, but I've run into a new problem.   I am repeated asked for my username and password.  After 3 attempts, I am told that I do not have permission to view the page.

I am controlling access to the directory using NTFS permissions on the file system.  It works great for small files, but it appears to forget who I am for large files.

Any help would be great.

Dennis