Issue with wordpress template

Hey guys, great forum. I stumbled here after searching around for a awhile and after contacting the theme developer who was no help.

So hopefully someone here can help! :thumbsup:

Alright,

The images below are from the top right of the screen. The Header Should expand and continue forever as it does on the left side , but here is the issue i am running into:

In Internet Explorer the site displays as I want it to :
http://i297.photobucket.com/albums/mm223/jamiecharlesgiannini/6-24-20109-55-07AM.jpg

But in Firefox , Opera and most others instead of just the option to scroll up and down the option to scroll left and right appears ( Which I don't want):
http://i297.photobucket.com/albums/mm223/jamiecharlesgiannini/6-24-20109-56-35AM.jpg

And if you scroll right it shows a small white section:
http://i297.photobucket.com/albums/mm223/jamiecharlesgiannini/6-24-20109-58-08AM.jpg

Is there an easy fix for this?
Anything I should look for in the theme editor?

Again, its a Wordpress theme.

Thanks Everyone!

Impossible to help without a link to your page, preferably, or failing that paste your code here.

Edited

The problem looks like it's here:

#topnav {
background:url("images/navbar-bg.jpg") repeat-x scroll center top #E6E6E6;
font-size:18px;
margin-left:20px;
padding:0;
width:100%;
}

You have the width of this div set to 100% plus a 20px margin - hence your page is wider than the screen and you get the horizontal scrollbar. I'd just remove the margin - it doesn't seem to be critical.

EDIT: I get the scrollbar in IE7 as well as FF, incidentally.

Many thanks! I sent you a message.