By default the database file is created in the same directory where the product is installed, which means that by default access rights to that file are the same as the default Administrator's - usually not writeable. To fix this change the access right for the database file. You can move the database file to any location on your computer, but do not forget to fix the reference in the configuration file (this can be done by Data Explorer -> Local Config -> Config Options -> dbname field also from Administrator account).

Note that networked database service also cannot be started from the more restricted account since the service must have the full access to the database file.