The Slash

One suggestion for improving SEO is to add trailing slashes to all pages. The point is that this can break your site, generating 404 error at almost every click that you’ll do.

The solution that I found was to edit the file app/code/core/Mage/Core/Model/Url/Rewrite.php and to replace the line:

$requestPath = trim($request->getPathInfo(), '/');

with the line

$requestPath = ltrim($request->getPathInfo(), '/');

I mean to replace the trim with ltrim