PLS-00306 error on call to cursor

CURSOR columnNames (inTableName IN VARCHAR2) IS
   SELECT COLUMN_NAME FROM USER_TAB_COLUMNS WHERE TABLE_NAME = inTableName;
/* Removed for brevity */
OPEN columnNames('TEMP');

FOR columnName IN columnNames LOOP

FOR columnName IN columnNames LOOP

create or replace procedure so_test_procedure as
 CURSOR columnNames (inTableName IN VARCHAR2) IS
   SELECT COLUMN_NAME FROM USER_TAB_COLUMNS WHERE TABLE_NAME = inTableName;
BEGIN
 OPEN columnNames('TEMP');
 CLOSE columnNames;
END;

procedure so_test_procedure Compiled.
execute so_test_procedure();

anonymous block completed