Handling of messages for FM GUI_UPLOAD

Hi All..

1) Iam using the FM GUI_UPLOAD for uploading a tab delimited file from the desktop/presentation server.

if the FM returns sy-subrc<> 0, i wanted to display the relevant error message. I would appreciate if any one could help me on how to handle these error messages display for different types of errors.

2) Also i got all the required records into an internal table itab and using a modify command to update the records to database table.

Modify dbtab from table itab.

If for some reason any errors occured in modify statement, please let me know how to handle those errors.

Thanks and will reward helpful answers.