User is importing an Excel sheet to a table using Import Table Data. He has to manually map table columns to Excel spreadsheet columns in Import Table Data as user's Excel columns do not have the same name as his table columns and they are not sequentially ordered. Import wizard shows a Field Mapping popup window and allows users to select automatic mapping by name or sequential mapping. User selects Cancel on this popup. When he clicks on the column title, Toad does not display the table column names and therefore he cannot manually map column.
Waiting for fix to be released in a future version of Toad for Oracle.