I append the end of my /etc/lighttpd/lighttpd.conf file - which works 
fine for me, maybe that helps. I do not use a specific wrapper, it is 
enough to have my cgi file set-uid (/var/www/backuppcBackupPC_Admin.cgi 
on my Mandriva platform)

Have you seen
http://backuppc.wiki.sourceforge.net/Install+Backuppc+with+Lighttpd

$HTTP["host"] =~ "^pcjuergen($|.unige.ch)" {
     $HTTP["url"] =~ "^/backuppc($|/)" {
         server.document-root = "/var/www/backuppc"
         alias.url = ( "/backuppc" => "/var/www/backuppc" )
         dir-listing.activate = "disable"
         index-file.names = ( "BackupPC_Admin.cgi" )
         $HTTP["remoteip"] != "127.0.0.1" {
             auth.backend = "htpasswd"
             auth.backend.htpasswd.userfile = "/server/www/passwd/backuppc"
             auth.require += ( "" => (   "method" => "basic",
                                         "realm" => "BackupPC",
                                         "require" => "valid-user" ) )
         }
     }
     $HTTP["url"] =~ "^/webdav($|/)" {
        $HTTP["url"] =~ "^/webdav/fox_" {
            server.document-root = "/server/www/foxmarks"
... snip ...
     }
}

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