Several factors were at work. A bit of time trouble was one of them, but there's not much to say about that in this context. Another factor may have been a lack of understanding about how to arrange the pawns on both sides of the board. We will look at that aspect of the ending with some care. Finally, a third factor was at play, one which can afflict a player at any stage of the game.
To grasp it, think of an analogy. Suppose someone arranges your couch so it's right in the middle of your living room, practically dividing it in half and make it difficult to get to the other side - or anywhere else, for that matter. If that happened, would you leave it there indefinitely, squeezing around or climbing over it? Of course not! You'd rearrange the furniture for your convenience and purposes. Man was not made for the sofa, but the sofa for man.
But when it comes to the placement of one's chess pieces, that common-sense adage is often overturned. If a piece is well placed, then players will often treat it like an immovable object, even if it gets in the way of everyone else doing their job. This is essentially what happened in this game, and while it cost the player with a knight half a point in his game, it can save us points in ours.
Enough preview - you can see the real thing here. It's free and available on-demand, so have a look!