The script is likely to time out if your server is running PHP-cgi instead of PHP-cli, and if you are using a batch period over 600 to 1200 seconds. A cron job might help in this case, though you'll probably have to explicitely reload every consecutive batch in your crontab file. You'll find an example titled "" in the documentation.
See also:
http://docs.phplist.com/PhpInterfacesInfo
Using a mailqueue throttle of 1 or 2 seconds might be a good idea in shared hosting environments.
You should keep in mind that sending 10,000 emails at a rate of 90 messages per hour will take about 5 days to send, and would require more than 100 reloads in your crontab file. It might therefore be easier to dispense with using batch processing and rely on a mailqueue throttle of 40 seconds to get the same 90 messages per hour rate.