Install FrontAccount into Synology NAS DS 107e

Hi,

I install FrontAccount into DS 107e, but there is an error as tmp folder is not writeable.

It cannot solve no matter
i). /tmp : chmod 777
ii). mkdir /test (chmod 777),  and change the setting in the session.inc as
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// Make sure this directory exists and is writable!
    $session_save_path = dirname(__FILE__).'/test/';
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The error is same below:
Warning: session_save_path() [function.session-save-path]: open_basedir restriction in effect. File() is not within the allowed path(s): (/volume1/web:/volume2/web:/volume3/web:/volume4/web:/volume5/web:/volume1/photo:/volume2/photo:/volume3/photo:/volume4/photo:/volume5/photo:/usr/syno/synoman:/etc:/var/run:/tmp:/var/spool/php:/volume1/@tmp/php:/var/services/web:/var/services/photo:/var/services/blog) in /volume1/web/FrontAccount/includes/session.inc on line 44

Any suggestion?

Thanks.