[Theme: Esplanade] Header Image Not Showing on IE

I’ve noticed that the header image on my blog (http://www.erichschuler.com/blog) doesn’t show on Internet Explorer, but it works find on Chrome, FireFox, and Safari.

I thought my cache plugin might be affecting this, but the header image would still not show after disabling it. I’m not sure what is causing this, but I would appreciate any leads.

http://wordpress.org/extend/themes/esplanade/