jQuery Grid Plugin - jqGrid

Using the default xmlReader, this data  works perfectly:

"<?xml version='1.0' encoding='utf-8'?>
<rows>
<page>1</page>
<total>1</total>
<records>2</records>
<row id='4'>
<cell>foo bar</cell>
<cell>5</cell>
<cell>4</cell>
<cell>1</cell>
<cell>3</cell>
<cell></cell>
</row>
<row id='3'>
<cell>bar bar</cell>
<cell>5</cell>
<cell>4</cell>
<cell>5</cell>
<cell>4</cell>
<cell></cell>
</row>
</rows>
"

Now all I do is add <userdata> and I get a parsererror:

"<?xml version='1.0' encoding='utf-8'?>

<userdata name="viewoption">22</userdata>

<rows>
<page>1</page>
<total>1</total>
<records>2</records>
<row id='4'>
<cell>foo bar</cell>
<cell>5</cell>
<cell>4</cell>
<cell>1</cell>
<cell>3</cell>
<cell></cell>
</row>
<row id='3'>
<cell>bar bar</cell>
<cell>5</cell>
<cell>4</cell>
<cell>5</cell>
<cell>4</cell>
<cell></cell>
</row>
</rows>
"

According to the documentation, this should work. Why isn't it working?