We have I believe the same issue. We have a webApp that does connect through sap connect and actually calls bapis to upload data into sap. that part works great. But when we have a different bapi to read a file (resume) from a web file location or even a sap server it does a cntrl_error. There should be a way to ID the sap system and make them a network user to access and load files. Please include me in any solutions out there.