By default, the license file (extension .lic) is expected on the same path like the database (extension .aipfile) and with the same name. If the license file is missing, a file with the same name like the All-In-One Player is searched. Only if the license file is on a different folder or has a different name, you have to specify the license file name with a start option.
-lf "path\file.lic" (lowercase letter l like license, f like file)
You can also use a configuration file to specify a license file.