Can't delete file from Files Backup

I am using Ghost 15 SP1, Window 7. I just backed up a large number of media files and accidentally included a large file that I didn't mean to backup. I found the file with the 'Files and Backup' method, right-mouse clicked and chose 'Delete...' Instead of deleting the file from the backup, it recovers it into my AppData\Local\Temp folder and then gives me an error message that the file cannot be deleted - access is denied. I do not know why this is happening. How can I delete this file? Shouldn't I be able to delte files from the Files and Folders backup?