preg_match(): Compilation failed: unmatched parentheses at offset 73

I could not figure out why the expression is incorrect.

            foreach ( (array) $rewrite as $match => $query ) {
                // If the requesting file is the anchor of the match, prepend it to the path info.
                if ( ! empty($req_uri) && strpos($match, $req_uri) === 0 && $req_uri != $request )
                    $request_match = $req_uri . '/' . $request;
                // LINE 207
                if ( preg_match( "#^$match#", $request_match, $matches ) || preg_match( "#^$match#", urldecode($request_match), $matches ) ) {

                    if ( $wp_rewrite->use_verbose_page_rules && preg_match( '/pagename=\$matches\[([0-9]+)\]/', $query, $varmatch ) ) {
                        // This is a verbose page match, let's check to be sure about it.
                        if ( ! get_page_by_path( $matches[ $varmatch[1] ] ) )
                            continue;
                    }

                    // Got a match.
                    $this->matched_rule = $match;
                    break;
                }

Warning: preg_match() [function.preg-match]: Compilation failed: unmatched parentheses at offset 73 in class-wp.php on line 207

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