WordPress database error MySQL server has gone away

Hi guys,
today i upgrade my wp blog to 2.8.5, but after upgrade, i can not access wp-admin/edit.php (other pages seem ok), this page is blank, display nothing……..
then i checked the error_log file , then i find the error:
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[14-Oct-2009 21:42:58] WordPress database error MySQL server has gone away for query SELECT t.*, tt.* FROM wp_terms AS t INNER JOIN wp_term_taxonomy AS tt ON t.term_id = tt.term_id WHERE tt.taxonomy IN (‘category’) AND tt.count > 0 ORDER BY t.name ASC made by require, require, require, require, wp_list_cats, wp_list_categories, get_categories, get_terms
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i also checked my database in phpmyadmin, wordpress tables seems ok,
and configures about database in wp-config.php is correct too!
so, anyone can help about this?
Thanks A Lot!
Miles