wp_head causing syntax error in IE7

Happy New Year, all. 🙂 The agency where I work is currently setting up a WP-powered site on a Windows server. A syntax error appearing in IE7 (disappearing on page reload) had us puzzled for a long time, until we discovered that removing the wp_head snippet would fix it. Now we are wondering if we have potentially broken anything on our site by removing this snippet? What kind of plugins rely on this snippet?

Also: what caused the snippet to generate the syntax error in the first place? Has anyone else experienced the same bug? The error was claimed to be in the second line, first character – which would be either the quotation mark in the middle of the doctype declaration or the starting bracket of the html tag, all depending.

Any input would be much appreciated! 🙂