[Plugin: Online Backup for WordPress] Online Backup WordPress timing out

when i backup using the plugin it always say
A timeout occurred during backup (large files and slow servers are the common cause of this); trying again…

i don’t have any video file in my wordpress
i host my wordpress on 000webhost

http://wordpress.org/extend/plugins/wponlinebackup/

log:
4th 五月 2012 8.42.31 下午 Information Deleted files processing completed.
4th 五月 2012 8.42.31 下午 Information File collection completed.
4th 五月 2012 8.37.31 下午 Information File system scan completed.
4th 五月 2012 8.37.31 下午 Information Folder /public_html/wp-content/plugins/wponlinebackup/tmp was excluded.
4th 五月 2012 8.37.28 下午 Information Folder /public_html/wp-admin was excluded.
4th 五月 2012 8.37.28 下午 Information Folder /public_html/wp-includes was excluded.
4th 五月 2012 8.37.28 下午 Information Database backup completed.
4th 五月 2012 8.37.26 下午 Information Initialisation completed.
4th 五月 2012 8.37.26 下午 Information Backup starting…

ps; i already try the dump_segment_size setting
sorry for the poor english