I've made snippets before but I must be overlooking something really simple; I cannot figure out where the error is in this snippet...

<CodeSnippet Format="1.0.0" xmlns="http://schemas.microsoft.com/VisualStudio/2005/CodeSnippet">
<Header>
    <Title>Throw NotImplementedException()</Title>
    <Author>olaffuB</Author>
    <Shortcut>nie</Shortcut>
    <Description>Quickly add a new NotImplementedException() to code.</Description>
    <SnippetTypes>
        <SnippetType>Expansion</SnippetType>
    </SnippetTypes>
</Header>
<Snippet>
    <Declarations>
        <Literal>
            <ID>TODO</ID>
            <Default></Default>
        </Literal>
    </Declarations>
    <Code Language="C#">
        <![CDATA[throw new NotImplementedException("$TODO$");    // TODO: $TODO$]]>
    </Code>
</Snippet>

Basically, when I got to import the snippet, it says that it is "invalid". The file name is "nie.snippet". Thanks!