I am a bit confused by your situation and would like to clarify a few things.
You are posting in a thread about the Harpoon Classic line of games that have a game screen that looks like this:
Is this the version of the game you are trying to get to work with the PlayersDB? If so, the answer to your problem is easy. The PlayersDB is made only to work with the Harpoon3 version that look like this:
and not the Harpoon Classic line of games.
If you are playing the Harpoon3 version of the game, then there are ways to get things to work. The scenarios work, but the PlayersDB installer was created to accommodate the file arrangement of the PC. I do not have a Mac so I am unaware of a different arrangement for Mac users as opposed to PC users (i.e. the file arrangement). I think that the simplest solution is to just run the PlayersDB installer to any empty folder. (After all, it is simply one big Zip file. It doesn't alter anything.) Then, you just move the various *.SCN, *.RES, *.DAT components out of that folder to their associated places in your installation.
For example, if the installer creates the folder, "Battlset" with all the *.DSD and *.SCN files within and your Mac installation has a folder named "Battleset" instead (with *.DSD and *.SCN files inside), you just move all the stuff over to it.
If this does not help you, please feel free to contact me directly and we can arrange an online chat. I am certain that your problem can be worked around. Sometimes, a few minutes of live chat can save endless hours of forum messages and e-mail.