eSearch Widget- use a field for the hyperlinkaliastext and get Error #1090

Hi: I would like to use field values to show up in the data grid instead of the URL. I have a field (PLATIMAGE) that I would like users to click and links them to open up a plat image. Instead of the URL, the text I would like to use is the plat name, which comes from another field, PLAT_NAME. I am using version 3.3 and in the help PDF it says:

"The hyperlinkaliastext attribute is the text or a {field} to show instead of the url in the data grid If you
want to use a field for the hyperlinkaliastext then just specify the name of the field in curly braces (i.e.
{DESCRIPTION}). So if you have a long url or just don't want the url to show in the data grid then you specify
the alias that you do want to appear in the data grid using this attribute."

Here is my config file:
<field name="PLATIMAGE" alias="Plat" gridfieldonly="true" hyperlinkgridfield="true" hyperlinkaliastext={PLAT_NAME} hyperlinkgridfieldonly="true"/>

I however get the following error when I try to launch the eSearch Widet:
"A problem occurred while parsing the configuration file widgets/eSearch/eSearchWidget_Layers.xml
Error #1090"

Is there something wrong with my xml file that I am missing?

Thanks!

Allison