You'll get that message when your browser doesn't know what to do with the data that is being returned to it. Try contentType="text/html".
Also, lose the <META> tag. It's not only redundant (since you indicated contentType on the <%@ page directive), it's positively dangerous. I just spent 3 weeks going stark raving mad because forms being submitted weren't providing the control values. Some clown had coded a META tag that redefined the content type.
Plus, I don't even guarantee that META content type will work properly on all browsers or all versions of IE or even individual versions of IE with different DOCTYPES (which I like to call their "select-a-bug" feature).
An IDE is no substitute for an Intelligent Developer.