Here the Solution:
The problem was crossing ids in the order tables so magento mixed up all items.
Solved this with truncating all order tables:
TRUNCATE sales_order;
TRUNCATE sales_order_datetime;
TRUNCATE sales_order_decimal;
TRUNCATE sales_order_entity;
TRUNCATE sales_order_entity_datetime;
TRUNCATE sales_order_entity_decimal;
TRUNCATE sales_order_entity_int;
TRUNCATE sales_order_entity_text;
TRUNCATE sales_order_entity_varchar;
TRUNCATE sales_order_int;
TRUNCATE sales_order_text;
TRUNCATE sales_order_tax;
TRUNCATE sales_order_varchar;
TRUNCATE sendfriend_log;
TRUNCATE tag;
TRUNCATE tag_relation;
TRUNCATE tag_summary;
TRUNCATE wishlist;
TRUNCATE log_quote;
TRUNCATE report_event;
TRUNCATE sales_flat_quote;
TRUNCATE sales_flat_quote_address;
TRUNCATE sales_flat_quote_address_item;
TRUNCATE sales_flat_quote_item;
TRUNCATE sales_flat_quote_item_option;
TRUNCATE sales_flat_quote_payment;
TRUNCATE sales_flat_quote_shipping_rate;
TRUNCATE sales_flat_order_item;
ALTER TABLE sales_order AUTO_INCREMENT=1;
ALTER TABLE sales_order_datetime AUTO_INCREMENT=1;
ALTER TABLE sales_order_decimal AUTO_INCREMENT=1;
ALTER TABLE sales_order_entity AUTO_INCREMENT=1;
ALTER TABLE sales_order_entity_datetime AUTO_INCREMENT=1;
ALTER TABLE sales_order_entity_decimal AUTO_INCREMENT=1;
ALTER TABLE sales_order_entity_int AUTO_INCREMENT=1;
ALTER TABLE sales_order_entity_text AUTO_INCREMENT=1;
ALTER TABLE sales_order_entity_varchar AUTO_INCREMENT=1;
ALTER TABLE sales_order_int AUTO_INCREMENT=1;
ALTER TABLE sales_order_text AUTO_INCREMENT=1;
ALTER TABLE sales_order_tax AUTO_INCREMENT=1;
ALTER TABLE sales_order_varchar AUTO_INCREMENT=1;
ALTER TABLE sendfriend_log AUTO_INCREMENT=1;
ALTER TABLE tag AUTO_INCREMENT=1;
ALTER TABLE tag_relation AUTO_INCREMENT=1;
ALTER TABLE tag_summary AUTO_INCREMENT=1;
ALTER TABLE wishlist AUTO_INCREMENT=1;
ALTER TABLE log_quote AUTO_INCREMENT=1;
ALTER TABLE report_event AUTO_INCREMENT=1;
ALTER TABLE sales_flat_quote AUTO_INCREMENT=1;
ALTER TABLE sales_flat_quote_address AUTO_INCREMENT=1;
ALTER TABLE sales_flat_quote_address_item AUTO_INCREMENT=1;
ALTER TABLE sales_flat_quote_item AUTO_INCREMENT=1;
ALTER TABLE sales_flat_quote_item_option AUTO_INCREMENT=1;
ALTER TABLE sales_flat_quote_payment AUTO_INCREMENT=1;
ALTER TABLE sales_flat_quote_shipping_rate AUTO_INCREMENT=1;
ALTER TABLE sales_flat_order_item AUTO_INCREMENT=1;