Redmine

I have a problem when I excute the step4
Step 4 - Update the database¶
This step is the one that could change the contents of your database. Go to your new redmine directory, then migrate your database:
rake db:migrate RAILS_ENV=production

I meet an error:a member_roles table already created. Then I rename the member_roles table to member_roles_saved as the upgrade guide told. Then restart the command:rake db:migrate RAILS_ENV=production . But a new error come up: mysql::Error: Can't create table '.\bitnami_redmine\member_roles.frm'<error 121>:CRTATE TABLE 'member_roles' <'id' int<11> DEFAULT NULL auto_increment PRIMARY KEY, 'member_id' int<11> NOT NULL, 'role_id' int<11> NOT NULL> ENGINE=InnoDB

Please help me to resolve the problem.

Thanks very much.