problem with ftp_put/upload files

Hello I would like to create a php script to upload file. With the POST method, I can't upload files whose size are more than 1 Mo (but my php.ini should allow up to 30 Mo, and the hidden field MAX_FILE_SIZE too!). So, I use a ftp connection to upload. But I have always the same error: Warning: error opening C:\folder\file.ext in /my/script.php when using ftp_put local server: linux RedHat 7.3, php 4.1.2, apache 1.3.23, proftpd 1.2.5 client: IE 5.5 on Windows NT Thanks Julien SObrier