My user is an admin user and I was trying to overwrite an existing file by uploading the updated file using the File Manager. But I got the following error:

An Error Has Occurred When Attempting To Save The File
(Path to file). Please
Contact Your Hosting Provider To Ensure The Appropriate Security
Settings Have Been Enabled On The Server.

My first impression was that the ASP.NET machine user did not have full rights but according to the site admin, the ASP.NET machine user does have full rights. The file had the file attribute 'A' next to it prior to my uploading error. But after the error the file attribute 'A' did not appear. I've tried to change the file attribute back but does not appear to stay. I've tried renaming and deleting the file so I can upload the updated version. However I get the following errors:

An error has occurred.
Error Renaming File:
Access to the path is denied.

and

Error Deleting File: Portal Root\\(Path to file)
   Access to the path "Portal Root\\(Path to file)" is denied.

I was able to upload a test file and then rename and delete the test file. I'm assuming that the issue lies with the specific file permissions itself. Is there any other possibilities?