auto-generated password incorrect in Safari

The auto-generated password is accepted under all browsers like FF, IE, Opera, Camino… but generally not under Safari. Here it produces the error notification: Incorrect password.
But when the auto-generated password is modified after a successful login under above mentioned browsers it is possible to login under Safari with the modified password.
Site is multi-author-site that has to allow a login with auto-generated password also in Safari.
Cleared cache, enabled cookies/cleared cookies, uploaded fresh wp-login.php without success.
Anyone any idea how to fix this?
Thanks a lot in advance!!!