Blank Screen in IE and Header / Background Question (NOOB)

I'm currently in the process of designing a new blog. Know a little bit about HTML and next to nothing about CSS. While designing, I'm trying to read up about CSS, but find sometimes it's easier to ask real people for help.

Currently, I have one problem and one question. I'm running Atahualpa Ver. 3.4.9 and WordPress Ver. 3.0. Still in the very early stages of design here and have already encountered a major problem. I have been working on the blog and always view it with Safari and Firefox and it looks as intended, but my partner on the blog just told me that it's blank on IE, which was confirmed by my girlfriend. Does anyone know why this is happening and how I can fix it? I'd love to leave as is, seeing as how I loathe IE, but I don't really want to exclude the many who use it as their primary browser.

The question I have is in regards to the header and background. I designed the header in Photoshop and have gotten it to fit right and to adjust to different screen resolutions, but was wondering how to make my page look like this blog: http://www.viget.com/inspire, in that the header kind of meshes with the background, which eventually fades into a repeating background. I hope that makes sense. I know he isn't using the same template, but it seems like this effect would be possible using Atahualpo. Is it accomplished with two different graphic files or one? The Photoshop part is easy for me. The coding part isn't and that's where I'm hoping someone can help.

My blog can be found at www.dudesofamerica.com. Thanks in advance for any help.