You'll get better/faster responses if you post your project here so we can take a look at what is going on.
That being said, I have had a similar issure only on the edges of the tilemap where the tiles aren't full tiles. For example, if the tiles are 30 pixels wide and the total width of the tilemap is, 290 the far right tile will never be able to be drawn. If your problem is specifically at the edge, check to make sure your tilemap width/height is a multiple of the individual tiles width/height.