Hello Litsa,
I really recommend to use a more recent ITS 6.20 patch! Patch level 19 is from August of 2005. The last available patch level (45) is from January of 2013. Please upgrade the ITS 6.20.
Note that you also should be using the Integrated ITS, as the ITS 6.20 is already out of maintenance.
You should check whether you have access to class cl_gui_frontend_services and test the upload from it.
Kind regards,
Cris