I don't know anything about that software. But if you figure out what ~ stands for (it's your user directory) then you might be able to use that. I suppose you could try
Code:
$chat_data_path = "~/TopCMM/123FlashChat9.6/server/data/default/";
but I can't remember offhand if you're allowed to use ~ with php functions or is it only works in shell commands. And even if it does work, I'm not sure the web server is running as that same user.