htaccess to escape percent (%) from URL

Having percent sign inside URL, returns bad request (error 400) to the browser. I have a filename that have percent (%) sign, resides at server.

Original File name:

204153_20090605_Aluminiumacetotartraat_DCB_oordruppels_1,2%.pdf

URL in browser after clicking on download link:

http://www.example.com/204153_20090605_Aluminiumacetotartraat_DCB_oordruppels_1%2C2%25.pdf

This returns 400 error with "bad request". I am using Kohana 3.

Existing .htaccess file contents are as follows:

RewriteEngine On

RewriteBase /

<Files .*>
Order Deny,Allow
Deny From All
</Files>

RewriteRule ^(?:application|modules|system)\b开发者_StackOverflow中文版.* index.php/$0 [L]

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d

RewriteRule .* index.php/$0 [PT] 

---

Try the B flag to ensure the %25, unescaped to % by mod_rewrite, is re-escaped back to %25 when inserted back into the target path.

RewriteRule .* index.php/$0 [PTB]