Why is this getting "invalid argument" error in IE8? (window.open)

            function popupLink(link){                
               var popup = window.open(link,'Facebook Share','menubar=0,开发者_StackOverflowdirectories=0,toolbar=0,resizable=1,status=0,location=0,width=500,height=350');
                if(!popup){
                    return true;
                }else{                    
                    return false;
                }
            };

 popupLink('http://www.facebook.com/sharer.php?u=http%3A%2F%2Fmsn.com%2F');

I just want to pop up a link...

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Window names cannot include spaces in IE. Change 'Facebook Share' to 'FacebookShare'