jQuery code blows up in IE

The following code causes an error in IE:

$("ul.sf-menu").supersubs({
    minWidth: 10,
    maxWidth: 30,
    extraWidth: 1
}).superfish();

The error is saying there is an invalid argument within the jquery.js file itself when the above code is run. 开发者_如何转开发What is the problem?

The problem doesn't happen with this:

$("ul.sf-menu").superfish();

So supersubs is causing a problem. Any ideas why though? IE isn't telling me what the actual issue is just that an invalid argument with something. And I can't use Firebug as there is no actual JS bug it's purely an IE problem with that code.

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Nothing wrong syntactically but the error could be happening inside supersubs() or superfish()