RFC_SYS_EXCEPTION RFC_IO27

Hello,

I call via RFC a FB in SAP named Z_ITESOFT_ARCHIV02 with some export parameters, the FB itself works correct but I get allways an exception back:

25.07.105 18:40:22.115 *** Calling RFC Function 'Z_ITESOFT_ARCHIV02'

25.07.105 18:40:22.161 RFC CALL status = RFC_SYS_EXCEPTION

25.07.105 18:40:22.161 RFC Error: RFC_IO27

-Status:CODE=CM_DEALLOCATED_NORMAL STATUS=CM_NO_STATUS_RECEIVED DATA=CM_COMPLETE_DATA_RECEIVED ID=28645066

-Message:connection closed

-Internal Status:IO HANDLE=1 DRV=EXT LINE=1400 CODE=27 : GET ID=ffff LINE=846 CODE=7

25.07.105 18:40:22.161 Function call finished.

FMFOSapRfc;25.07.05;18:40:22;[Info ];ITESOFT;FMFOSapRfc.iCON:LinkBarcode;Func.Call failed: 3 | 'SYSTEM_FAILURE'

here the code snippet in VB:

Set Func = SapFuncs.Add(strFuncLinkBcd)

Func.Exports("IDOCNUM") = strDocnum

Func.Exports("BCODE") = strBarcode

Func.Exports("LOG_SYSTEM") = ""

Func.Exports("CLASSNAME") = strClassname ' from ini file

Func.Exports("CLASSTYPE") = strClasstype ' from ini file

Func.Exports("CONTREP") = strContrep ' from ini file

Func.Exports("DOCUTYPE") = strDocutype ' from ini file

Func.Exports("BDSBARCOM") = strBdsbarcom ' from ini file

CallOk = Func.Call

SapRet = Func.ReturnCode

Any ideas why I get allways this error?

Enrico