.htaccess and the HIGH CPU %

everytime I upload a “.htaccess” to “/var/www/blog/”, the CPU % in the VPS Manager will suddenly become HIGH!

like this screenshot:
http://i-left.com/temp/2008-08-09_232050.png

here is content of “.htaccess”:
RewriteEngine On
RewriteBase /blog/
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /blog/index.php [L]

this “.htaccess” generated by WordPress

and I tried this method:
http://forum.slicehost.com/comments.php?DiscussionID=2116

but it is not work for my site
the CPU % also will suddenly become HIGH……