Crash when installing on site with many custom group defined

Created by: samuelsov

I have the following error on install - apparently it tries to create custom table with an custom_group_id that is already used (id=9) :

Apr 08 20:21:18  [error] $Fatal Error Details = Array
(
    [callback] => Array
        (
            [0] => CRM_Core_Error
            [1] => exceptionHandler
        )

    [code] => -5
    [message] => DB Error: already exists
    [mode] => 16
    [debug_info] => CREATE TABLE civicrm_value_event_terms_and_conditions_acceptance_9 (
        `id` int unsigned NOT NULL AUTO_INCREMENT COMMENT 'Default MySQL primary key',
        `entity_id` int unsigned NOT NULL COMMENT 'Table that this extends',
        PRIMARY KEY ( id ),
        UNIQUE INDEX unique_entity_id (  entity_id ),
        CONSTRAINT FK_civicrm_value_event_terms_and_co_89e8a6f330ba6697 FOREIGN KEY ( `entity_id` ) REFERENCES civicrm_activity ( id ) ON DE
) ENGINE=InnoDB DEFAULT CHARACTER SET utf8 COLLATE utf8_unicode_ci; [nativecode=1050 ** Table 'civicrm_value_event_terms_and_conditions_acce
    [type] => DB_Error
    [user_info] => CREATE TABLE civicrm_value_event_terms_and_conditions_acceptance_9 (
        `id` int unsigned NOT NULL AUTO_INCREMENT COMMENT 'Default MySQL primary key',
        `entity_id` int unsigned NOT NULL COMMENT 'Table that this extends',
        PRIMARY KEY ( id ),
        UNIQUE INDEX unique_entity_id (  entity_id ),
        CONSTRAINT FK_civicrm_value_event_terms_and_co_89e8a6f330ba6697 FOREIGN KEY ( `entity_id` ) REFERENCES civicrm_activity ( id ) ON DE
) ENGINE=InnoDB DEFAULT CHARACTER SET utf8 COLLATE utf8_unicode_ci; [nativecode=1050 ** Table 'civicrm_value_event_terms_and_conditions_acce
    [to_string] => [db_error: message="DB Error: already exists" code=-5 mode=callback callback=CRM_Core_Error::exceptionHandler prefix="" i
        `id` int unsigned NOT NULL AUTO_INCREMENT COMMENT 'Default MySQL primary key',
        `entity_id` int unsigned NOT NULL COMMENT 'Table that this extends',
        PRIMARY KEY ( id ),
        UNIQUE INDEX unique_entity_id (  entity_id ),
        CONSTRAINT FK_civicrm_value_event_terms_and_co_89e8a6f330ba6697 FOREIGN KEY ( `entity_id` ) REFERENCES civicrm_activity ( id ) ON DE
) ENGINE=InnoDB DEFAULT CHARACTER SET utf8 COLLATE utf8_unicode_ci; [nativecode=1050 ** Table 'civicrm_value_event_terms_and_conditions_acce
)