Under Debian, the installation of PHP-CLI has no default support of the mysql extension - one has to uncomment it in the php.ini for CLI (/etc/php4/cli/php.ini).
Unfortunatly ezpublish gives no appropriate error message, it just aborts script-execution as quoted above - an error like this would have saved me half a day's time ;-)
But maybe this posting can help some other cli-newbies?