Commit and Rollback in one step

Hi, I’m working on a SQL2000 server. I have designed a dataport which reads orders from a text file. When for example I have 10 orders and the 5 raise an error the system has save the 3 of them. I have no special code, just insert(true). This is not happened for Navision server. What’s goes on? I need to handle all the orders as one transaction. Thanks in advance