This was reported by omatichyn on the upgrading page of Mantis manual:
http://manual.mantisbt.org/manual.installation.upgrading.php

I cannot upgrade my 0.19 version to 1.0.0rc1 I use http://localhost/admin/install.php
but error appears
BAD
CREATE TABLE mantis_bug_file_table ( id INTEGER UNSIGNED NOT NULL AUTO_INCREMENT, bug_id INTEGER UNSIGNED NOT NULL DEFAULT 0, title VARCHAR(250) NOT NULL DEFAULT '', description VARCHAR(250) NOT NULL DEFAULT '', diskfile VARCHAR(250) NOT NULL DEFAULT '', filename VARCHAR(250) NOT NULL DEFAULT '', folder VARCHAR(250) NOT NULL DEFAULT '', filesize INTEGER NOT NULL DEFAULT 0, file_type VARCHAR(250) NOT NULL DEFAULT '', date_added DATETIME NOT NULL DEFAULT '1970-01-01 00:00:01', content LONGBLOB NOT NULL, PRIMARY KEY (id) )TYPE=MyISAM Table 'mantis_bug_file_table' already exists

upgrade script tryes to create existing table. How I can workaround this proplem?
thanks in advance for answer