Try:
ALTER TABLE `panel_customers` ADD COLUMN `backup_allowed` TINYINT( 1 ) NOT NULL DEFAULT '1';
ALTER TABLE `panel_customers` ADD COLUMN `backup_enabled` TINYINT( 1 ) NOT NULL DEFAULT '0';
I think it is related with #742 (http://redmine.froxlor.org/issues/742)
Edit: Now corrected. Thanks to RipCaw.