Make sure the ground you start on is set to passable. I've noticed a problem with starting on any ground above Layer 1 for RPG Maker XP.
Also if you hold the ctrl key you can walk over anything no matter what (as long as you're in test play). Make sure you're using the arrow keys and that you have that window selected, selecting another window will make you unable to do anything.
Also, I've never seen this question asked before so I don't think it's a noob question. Just an unlucky chance that it happened to you =/