This might fix your problem. In your .htaccess file you probably have something like this :
RewriteRule ^(.*)$ /index.php/$1 [L,QSA,PT]
RewriteRule .* /index.php [NS,L]
If that is so, just simply remove the leading "/" from the index.php then save it.
Refresh the page. And voila! The issue should be fixed now.