It says bad username/password, is it because noone is in the teamspeak server?

This isn't a teamspeak forum.

http://forum.goteamspeak.com/

you only are supposed to put in a username and password if you're registered on the server you're trying to connect to. If you're not (which you won't be if it is your first time connecting to that server, you would also know if you registered before.

In short, don't try using a username/pasword, instead choose "Anonymous" and choose a nickname