I found this reference:
"when you get the product search result error by applying the template in powerstore to a newly created page this is what you get. "
Not sure if this applies to you.
This is what I have (unmodified):
<div id="searchBox">
<form id="searchForm" method="get" action="Products_Results.php" >
<input name="Search" type="submit" value="Search" id="Search" alt="Search" />
<input type="text" name="S_ProductName" id="S_ProductName" />
</form>
</div>