Hola, tengo un error desde ya hace un tiempo de cuando cambie el foro de hosting y no eh podido encontrar el porque del problema, le comente al hosting pero dicen que todo va bien. El foro anda bien solo que al responder una publicación o crear un nuevo tema con varios enlaces o imagenes y se presiona vista previa o publicar, me envia un error 404/403, no entiendo cual es el motivo, esto es lo que me aparece:

Revise los permisos de las carpetas (755) y los archivos (644) pero nada que se soluciona.
Revise el log de errores del servidor y me muestra esto:
[Mon May 13 13:07:14 2013] [error] [client 200.180.3.120] File does not exist: /home/sentimie/public_html/404.shtml, referer: http://www.sentimiento-vallenato.com/index.php?board=34.0
[Mon May 13 12:46:12 2013] [error] [client 200.180.3.120] File does not exist: /home/sentimie/public_html/403.shtml, referer: http://www.sentimiento-vallenato.com/index.php?action=post;quote=24713;topic=2222.0;last_msg=24713
[Mon May 13 12:46:11 2013] [error] [client 200.180.3.120] File does not exist: /home/sentimie/public_html/403.shtml, referer: http://www.sentimiento-vallenato.com/index.php?action=post;quote=24713;topic=2222.0;last_msg=24713
Dejo un usuario para probar lo que comento
usuerio: prueba
contraseña: password123
Tema donde hacer la prueba: http://www.sentimiento-vallenato.com/index.php?topic=2224.0
Copiar el siguiente contenido e intentar publicarlo o solo ver vista previa:
[quote]
Forbidden
You don't have permission to access /index.php on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
Apache/2.2.24 (Unix) mod_ssl/2.2.24 OpenSSL/0.9.8e-fips-rhel5 mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635 Server at [url=http://www.sentimiento-vallenato.com]www.sentimiento-vallenato.com[/url] Port 80
[/quote]
[quote]
Forbidden
You don't have permission to access /index.php on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
Apache/2.2.24 (Unix) mod_ssl/2.2.24 OpenSSL/0.9.8e-fips-rhel5 mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635 Server at [url=http://www.sentimiento-vallenato.com]www.sentimiento-vallenato.com[/url] Port 80
[/quote]
[quote]
Forbidden
You don't have permission to access /index.php on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
Apache/2.2.24 (Unix) mod_ssl/2.2.24 OpenSSL/0.9.8e-fips-rhel5 mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635 Server at [url=http://www.sentimiento-vallenato.com]www.sentimiento-vallenato.com[/url] Port 80
[/quote]
[quote]
Forbidden
You don't have permission to access /index.php on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
Apache/2.2.24 (Unix) mod_ssl/2.2.24 OpenSSL/0.9.8e-fips-rhel5 mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635 Server at [url=http://www.sentimiento-vallenato.com]www.sentimiento-vallenato.com[/url] Port 80
[/quote]
[quote]
Forbidden
You don't have permission to access /index.php on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
Apache/2.2.24 (Unix) mod_ssl/2.2.24 OpenSSL/0.9.8e-fips-rhel5 mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635 Server at [url=http://www.sentimiento-vallenato.com]www.sentimiento-vallenato.com[/url] Port 80
[/quote]
[quote]
Forbidden
You don't have permission to access /index.php on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
Apache/2.2.24 (Unix) mod_ssl/2.2.24 OpenSSL/0.9.8e-fips-rhel5 mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635 Server at [url=http://www.sentimiento-vallenato.com]www.sentimiento-vallenato.com[/url] Port 80
[/quote]
[quote]
Forbidden
You don't have permission to access /index.php on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
Apache/2.2.24 (Unix) mod_ssl/2.2.24 OpenSSL/0.9.8e-fips-rhel5 mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635 Server at [url=http://www.sentimiento-vallenato.com]www.sentimiento-vallenato.com[/url] Port 80
[/quote]
[quote]
Forbidden
You don't have permission to access /index.php on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
Apache/2.2.24 (Unix) mod_ssl/2.2.24 OpenSSL/0.9.8e-fips-rhel5 mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635 Server at [url=http://www.sentimiento-vallenato.com]www.sentimiento-vallenato.com[/url] Port 80
[/quote]
Que podrá lo que cause el error? Gracias de antemano por su ayuda
Saludos