I don't use Suse, but I think your problem came about from not following the default install. Most linuxes but the websites in something like /var/www, /var/www/html, /var/html, or something along those lines. There isn't a problem putting it anywhere you choose, but you have to get the permissions right.
As to BackupPC, if it was installed by your package manager, and not from source, then it probably placed the storage files in the /var/www/* setup. BackupPC in particular can get tricky with permissions, as the apache user needs access to some of the files, but the backuppc user needs most of them. Sometimes you have to play some tricks to get files set with the correct users and groups. Like I said above, its fine to put any files anywhere on a *nix system, but you have to have a very good understanding of the permissions system. 777 is only okay in something like /tmp, never for a working directory, particularly not a website.
If Suse did put your websites in /srv/www, then it should have worked from the get go. Did you try http://localhost/backuppc
, or http://localhost/cgi-bin/backuppc/BackupPC_Admin
, or http://localhost/backuppc/BackupPC_Admin
? Even with only one website, it generally won't direct you to it unless you call for it specifically.