Hi, look this is error
The mod rewrite in server as enable 
The configuration in fileserver.
FS1.myhost.com
Code:
- Testing mod rewrite and .htaccess file... Could not validate that the .htaccess file had been created on the file server or that mod rewrite was enabled, please check and try again.The configuration in fileserver.
FS1.myhost.com
Code:
RewriteEngine On
RewriteBase /
RewriteRule ^(.+)\~s$ '.WEB_ROOT.'/$1~s [L]
RewriteRule ^(.+)\~i$ '.WEB_ROOT.'/$1~i [QSA,L]
RewriteCond %{REQUEST_URI} ^(.+)\~d$
RewriteRule ^(.*) delete_file.php?u=$1 [QSA,L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond $1 !\.html$
RewriteRule ^(.*) file_download.php?u=$1 [QSA,L]
RewriteRule ^(.*).html$ $1.php [QSA,L]
Code:
/* main configuration file for script */
define("_CONFIG_SITE_HOST_URL", "FS1.myhost.com");
define("_CONFIG_SITE_FULL_URL", "FS1.myhost.com");
define("_CONFIG_CORE_SITE_HOST_URL", "myhost.com");
define("_CONFIG_CORE_SITE_FULL_URL", "myhost.com");