install.php and valid.inc missing marks your roster dir as CRITICAL. As you have to delete the first and want to delete the latter it seems a bit contraproductive to mark this critical?
2nd:
-logging in as admin
-pressing the Roster Diag button gives me the Diag screen
but with another Admin login box and NO download option for my file diff.
When I log in my admin password into that login box (again) nothing chances, but If I enter a wrong password there I get Invalid password, the login box vanishes and now I have the radio buttons down by the file list to choice between zip and tar download of the diff files.