You may encounter issue when downloading file via webgui. You are requested to send the java console trace. Below is the procedure.
1. Go to Control Panels and choose Java.
2. In the Java control panel go to "Advanced" tab.
3. In "Java console" section select "Show console" option.
4. Start Webgui and reproduce the problem.
5. After below Java Console is launched, press 5 (depends on what SAP consultant requests) to set the trace level to 5.
6. Save the trace in .txt format and attach to the incident.