Users get a download windows when accesing the site

Hello!

I recently published my brand new portfolio using WordPress. Everything is going well but one thing: In Safari and Internet Explorer, when you access the page, there appears a download window instead of the website, and I have no idea why is this happening.

The site is this: http://aegis-strife.net

In the rest of browsers it works fine, at least for me :/

Has it something to do with caching or somwthing like that? I use W3 total cache.

Thanks beforehand!