Placement of custom template problem & another small thing

[Krysia]

Hi there,

I've upgraded to the latest RC release, and have run into the following problem. (I took screenshots because I think it's easier to simply show.)
(click thumbnails for larger image)

The latest RC release:



How the white portion of the page is supposed to be (note there's no margin on the left side of the page, the white goes right up against the side of the window):


Basically, I can't figure out how to make it so the (first image) white part is up against the left side of the page like with the second image below. The header and footer are the same as they were prior to the upgrade; no changes there. But now, as you can see, there's a gap of background color in between the side of the window and the start of the white. You can also tell that it isn't supposed to be there, as the border stops.

And speaking of stopped borders...
If you look at the first image, you'll notice in the menu (after "logout") that the image for the right side border (maintab last) isn't showing up. I made one to match the color scheme, as I did with the others, but that refuses to appear, as does its "mirror" counterpart. Does anyone have any idea why?

Thank you! 

[Krysia]

Is this something related to "header" or "footer" for customization?