Administration - Installation - Core: update from 6.0 to 6.4

Hello,

The vesrion 6.0 was running correctly...

After 6.4 version installation ...

...when I try to access "setup" with "http://xxxxxxxxxx/ilias/setup/setup.php" the firefox system answer me  "the page is not redirected correctly" and URL became "http://xxxxxxxxxx/ilias/setup/setup.php?" (with "?" at the end)

An idea???

Thank you

Laurent