Thanks, I 'll try to unshadow the password, but I m not the adminstrator of the Informix Server and he say it's not possible.
Do you know what don't work the ODBC connection with a user without password?
(When I connect to server via telnet whit the user without password the unix system ask for putting a password, it seams the unix system don't like users without password, I think it's the cause of the users without password don't work)