How to prevent automatic log out of inactive sessions?

Hello Drupalians,
Please help me with this issue.I have a staging site built with drupal6 running in an external hosting environment.If i leave my site with no action for more than 10 minutes + then am automatically logged out.I tried all the possible ways altering the session related variables in the settings.php but no solution found and also i checked with my hosting side and they too say that the problem is not from their end.

Below given are the values from my settings.php file:
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ini_set('arg_separator.output','&');
ini_set('magic_quotes_runtime',0);
ini_set('magic_quotes_sybase',0);
ini_set('session.cache_expire',30000);/*As i want the user to be signed out after 8 hrs*/
ini_set('session.cache_limiter','none');
ini_set('session.cookie_lifetime',0);
ini_set('session.gc_maxlifetime',0);/*As i want to clear the session as soon as the browser is closed*/
ini_set('session.save_handler','user');
ini_set('session.use_only_cookies',0);
ini_set('session.use_trans_sid',0);
ini_set('url_rewriter.tags','');

Please let me know what might me the problem?Thanks in advance.