Unidentified error: On the first screen in SAP ("SAP Easy access") I get a GuiXT error (GuiXT triangle red) but no error is shown in the script window. How can I find the error?

This is probably caused by an error in  your session script (d.session.txt, e.sesseion.txt, etc.). You can check it in the GuiXT script editor with the "syntax check" button.