Works in Firefox, ERROR in IE - help!

[bpops]

I have submitted snippets of this code before. The site I am creating works fine in Firefox, but throws back an error in IE. Here is the url:

http://www.b-pops.com/boxartist/gc.shtml

If anyone can tell me why this doesn't work in IE, I would be extremely grateful. I've been working on this for quite a while with no success.

As you'll see, the page updates automatically in Firefox. You can change background colors, add a title, etc. IE however, gives errors that I can't track down.

Also, here is the javascript that I'm using (included in the header of that page):

[code]
// JavaScript Document

function change_bg(){

var image_url = create.background.value;
var color = create.bg_color.value;
var repeat = create.bg_repeat.value;
var position_vert = create.bg_position_vert.value;
var position_hor = create.bg_position_hor.value;

box = document.getElementById('box');
position = position_vert+' '+position_hor;

box.style.backgroundImage = 'url("'+image_url+'")';
if (color){
box.style.backgroundColor = color;
}
box.style.backgroundRepeat = repeat;
box.style.backgroundPosition = position;


}

function change_title(){

var title = document.create.title.value;
var title = title.replace('\n', '<br>');
var font_family = document.create.font_family.value;
var font_custom = document.create.font_custom.value;
var font_size = document.create.font_size.value;
var font_color = document.create.font_color.value;
var font_style = document.create.font_style.value;
var title_position_vert = document.create.title_position_vert.value;
var title_position_hor = document.create.title_position_hor.value;

main = document.getElementById('main');
if(font_family == 'custom'){
font_family = font_custom;
}

main.innerHTML = title;
if(font_color){
main.style.color = font_color;
}
main.style.fontFamily = font_family;
main.style.fontSize = font_size;
main.style.color = font_color;
main.style.fontWeight = font_style;
main.style.textAlign = title_position_hor;
main.style.verticalAlign = title_position_vert;

}

/*function change_esrb(rating){
esrb = document.getElementById('esrb');

rating = 'images/logos/'+rating;
esrb.src = rating;

}*/

function change_patch(image,patch_num){
if(image == 'custom'){
if(patch_num == 'patch_1'){
image = document.create.patch_1_custom.value;
}
if(patch_num == 'patch_2'){
image = document.create.patch_2_custom.value;
}
if(patch_num == 'patch_3'){
image = document.create.patch_3_custom.value;
}
}else{
image = 'images/logos/'+image;
}

patch_num = document.getElementById(patch_num);
patch_num.src = image;

}

function only_for(image){
image = 'images/logos/'+image;
only_img = document.getElementById('only_img');
if(document.create.only.checked){
only_img.src = image;
}else{
only_img.src = 'images/logos/blank.gif';
}

}
[/code]

[fenway]

Seems to work in IE7, as far as I can see... I'll have to wait until I get home to test in on IE6.