I believe you are trying to download an application to the device connected which is to the clientcontrol.
Clientcontrol download code supports only RAM download in my knowledge. (with .hcd file).
If you are tying to download an application to the flash, then I would suggest you to use chipload or WICED/MODUS IDE.
"but only once was successfull" -> Did you confirm that the device successfully loaded the firmware and started running the application?Which WICED version (clientcontrol version) are you using?