Roger, SeanM has already told the foolproof way: navigate to the page you want to link to and copy its address.

If you use two slashes after the protocol (http:, https:, ftp:, gopher:, ...), you have to provide the server name as well (like www.mudcat.org), otherwise only the path to the file (relative to the server root or current file). So here in Mudcat it should be safest to use one or no slash (as there is more than one server: www, ragtime, loki, shorty).
Which of the two is better? Can't say! Probably no slash, as Netscape 6 has problems with server-relative paths. Otherwise, no big difference.

MudGuard