proftp problems

[ivenio]

hello urgent
hello have a very important problem with the servant ftp on having tried on writing the files mistake says 550 to me.

That can be?

He is the server proftpd + fedora core 5

--------- ERROR ---------------------
*** CuteFTP 7.0 - build Mar 30 2006 ***

STATUS:> Transferring file "/domains/nintendoforest.com/public_html/actualizaciones.php"...

STATUS:> Checking directory existence: "/domains/nintendoforest.com/public_html".

STATUS:> Remote directory already exists: "/domains/nintendoforest.com/public_html".

COMMAND:> SIZE actualizaciones.php

550 SIZE: Operation not permitted

STATUS:> Requested action not taken (e.g., file or directory not found, no access).

COMMAND:> CWD /domains/nintendoforest.com/public_html/actualizaciones.php

550 /domains/nintendoforest.com/public_html/actualizaciones.php: Not a directory

STATUS:> Requested action not taken (e.g., file or directory not found, no access).

COMMAND:> CWD /domains/nintendoforest.com/public_html

250 CWD command successful

STATUS:> PWD skipped. Current folder: "/domains/nintendoforest.com/public_html".

COMMAND:> PASV

227 Entering Passive Mode (85,25,132,94,146,176).

COMMAND:> STOR actualizaciones.php

STATUS:> Connecting FTP data socket 85.25.132.94:37552...

550 actualizaciones.php: Permission denied

ERROR:> Requested action not taken (e.g., file or directory not found, no access).