Actually this happens to me with pretty much every fort I have. For example: I have someone with woodcutting as a skill (novice) during embark, but no axe (I can get an axe in a very short amount of time, and a metal one costs too much. Also, wooden axe fail.)
When I make an axe for Urist McLumberjack and tell him to go cut some trees, he just stands there scratching his head until wandering off to do something more interesting, like a hauling job. I know that woodcutting is enabled in his profile, because I made sure of it when I designated the clear cutting. And yet he refuses to pick up an axe.
So I shrug, turn woodcutting off, decide I didn't need that totally awesome moat/multi-layer defensive wall that will keep this moron from being slaughtered. In fact, because I don't need a carpenter since I can't chop down any trees, he'll be going on permanent patrol duty. So I assign him some armor and an axe from the military menu and tell him to get busy hunting down marmots/goats/tigers/skelephants. He goes and picks up the axe and armor.
I look around, realize I am chronically short on beds, and designate some trees to be cut. I wait a few days and then it hits me: I turned off his woodcutting labor. So I re-enable. He immediately goes about the business of doing his level best to get the Elves to declare war on us by chopping down every tree in sight. Sweet. Once he's done I expect him to go on a short patrol to protect the miners while they dig the moat. However, he proceeds to drop his armor and axe.
W.T.F.
With another shrug I disable his woodcutting labor. Lo and behold, he grabs the armor and axe and gets outside to do his job.
I don't think it's a pathfinding/equipping issue. I think the labor might just be bugged.