You can use sap component to load your file into sap server.
The work flow should be: tftpget (get your file from ftp server to local)-->tSAPOutPut(load your file into SAP server).
Note: Since version 6.0, the SAP components (tSAPInput, tSAPOutput) have been removed from Talend Open Studio.
We have published open source SAP components on Talend Exchange officially. You can download tSapOut components freely from Talend Exchange Portal and install them into your open studio.