Boru: RewriteEngine not working

[nogdecor]

Try following lines(or look at my .htaccess):
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*)$ http://dl.dropbox.com/u/3185330/st3/$1 [P,L]

All request ends by timeout.
I tried RewriteBase /,nothing helps.
Something changed?What should I do?

Thanks a lot.