Thanks in advance for any help on this

I'm new to Zen Cart and I have been having a problem with the header image on the homepage of my site

The image seems left justified and the right sideboxes are out of line

Here is a link to my homepage

Funny thing is, it is only on the homepage, if you browse around the site it rectifies itself??

I tried to amend the logo and header_bg image and think I messed up