Change comments

I have a problem with the comments. To best describe it, my homepage url is http://www.pastiladeras.ro
The page is currently under construction, but once you load it using Internet Explorer you will see an error “Internet explorer cannot open ……” (If not shown, try refreshing a few times)
The problem comes from the comment textarea – scroll down to see. Inside it the “The page cannot be displayed” error is displayed.

How can I change the entire comment sistem and you the default wordpress one ?
I already tried replacing comments.php from inside the theme’s directory, but that doesn’t seem to be a solution. (I get other errors and no comment form is displayed)

No problem when using Firefox – just Internet Explorer
Thank you!