FOSS gamedev and creative worlds

I downloaded the game, but know I can't get it to recognize a password.

You dont need a password to play singleplayer.
On multiplayer you can play without a password, but you can set one if you want to (and some servers force you to set a password when connecting first).
To set up a password for a multiplayer server either type a password in the main menu when connecting, or click on "Change Password" in the pause menu.

Now it's still complaining about "Illegal Instruction I'm not sure whats wrong.

Please post your debug.txt as described here: http://forum.minetest.net/viewtopic.php?id=5073

csuell791 wrote:Now it's still complaining about "Illegal Instruction I'm not sure whats wrong.

Are you trying to use 'illegal' characters in your name and/or password. I always forget what's not allowed, but at least it should accept letters, numbers and CAPS.