Salem

My friend and I did the starting quest, and we decided one of us (him) should talk to the guide and go to the wilderness, while the other (me) would then talk to the guide to teleport to the same location. But when I put my friend's homestead secret I get a "That player has not yet settled" message. What's the problem here?

your friend needs to have a claim for you to spawn there, not just a leanto.
check stickied FAQ

He needs to build one of these first > http://salemwiki.info/index.php/Stake_Claim

i put a claim on my land but my friend still cant get there...what am i doing wrong

Make the claim your homestead. Set a homestead secret. Give that to your friend, and have him type that in the white box in Boston when talking to the wilderness guide.

also hit the "Enter" key on the keyboard after entering homestead secret, instead of the "use wildness guide" in-game selection button.

Also make sure there is enough clear space on the claim for their lean-to to spawn.