Search notes:

ORA-29280: invalid directory object

The error ORA-29280: invalid directory object might be thrown if a directory name is specified in the wrong case (it typically should be uppercase).
create directory ext_dir as …;

begin
   utl_file.fremove (
      location => 'ext_dir',  -- Throws error if directory name is in lowercase
      filename => 'data.csv'
   );
end;
/

See also

The directory object
Other Oracle error messages such as ORA-29283: invalid file operation

Index

Fatal error: Uncaught PDOException: SQLSTATE[HY000]: General error: 8 attempt to write a readonly database in /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php:78 Stack trace: #0 /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php(78): PDOStatement->execute(Array) #1 /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php(30): insert_webrequest_('/notes/developm...', 1759428097, '216.73.216.42', 'Mozilla/5.0 App...', NULL) #2 /home/httpd/vhosts/renenyffenegger.ch/httpsdocs/notes/development/databases/Oracle/errors/ORA-29280_invalid-directory-object(50): insert_webrequest() #3 {main} thrown in /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php on line 78