WP Super Cache – Help sought

Recently, I’ve started getting following error, when I click update button on “WP Super Cache Status” options from Super Cache options page:

Warning: rename(/home/.xxx/xxxx/ditii.com/blog/wp-content/cache/supercache/www.ditii.com.disabled,/home/xxx/xxxx/ditii.com/blog/wp-content/cache/supercache/www.ditii.com) [function.rename]: Device or resource busy in /home/xxx/xxxx/ditii.com/blog/wp-content/plugins/wp-super-cache/wp-cache.php on line 623

Once, I exit and re-load Super Cache options page, the doesn’t appear. Can anyone advice, why it’s happening?

Also, the plugin is not serving Super Cache page, I’ve my blog installed as follows:

WP URI: https://www.ditii.com/blog
Blog URI: https://www.ditii.com/

My existing htaccess rules as follows:

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{QUERY_STRING} !.*s=.*
RewriteCond %{HTTP_COOKIE} !^.*comment_author_.*$
RewriteCond %{HTTP_COOKIE} !^.*wordpress.*$
RewriteCond %{HTTP_COOKIE} !^.*wp-postpass_.*$
RewriteCond %{HTTP:Accept-Encoding} gzip
RewriteCond %{DOCUMENT_ROOT}/wp-content/cache/supercache/%{HTTP_HOST}/$1index.html.gz -f
RewriteRule ^(.*) /wp-content/cache/supercache/%{HTTP_HOST}/$1index.html.gz [L]

RewriteCond %{QUERY_STRING} !.*s=.*
RewriteCond %{HTTP_COOKIE} !^.*comment_author_.*$
RewriteCond %{HTTP_COOKIE} !^.*wordpress.*$
RewriteCond %{HTTP_COOKIE} !^.*wp-postpass_.*$
RewriteCond %{DOCUMENT_ROOT}/wp-content/cache/supercache/%{HTTP_HOST}/$1index.html -f
RewriteRule ^(.*) /wp-content/cache/supercache/%{HTTP_HOST}/$1index.html [L]

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]

</IfModule>
# END WordPress

Help me getting out of the degraded performance, and lots of suspensions, that the ISP is giving on daily basis on the pretext, I’m using lots of their Server resources.