CGI.pm is expecting params to arrive uuencoded per the cgi standard.. The '/lost+found' string will be properly encoded by the browser when it stumbits, but you need to code by hand for local testing. Examples:

$ perl -MCGI -e'$q=CGI->new;print $q->param(q/dir/),$/' dir='/lost+fou
+nd'
/lost found
$ perl -MCGI -e'$q=CGI->new;print $q->param(q/dir/),$/' dir='/lost%2Bf
+ound'
/lost+found
$
[download]

The first verifies your results, the second shows how to encode.

After Compline,
Zaxo