There is no columnName column in the query object.
Sample code
<cfset QuerySetCell(queryName, "columnValue", 1)>
Explanation
You'll get this error if you forget to specify a column name in this function:
<cfset QuerySetCell(queryName, "columnName", "columnValue", 1)>
<cfset QuerySetCell(queryName, "columnName", "columnValue", 1)>
Submitted by Duncan Cumming on Tuesday 14 October 2008

Posted by Adrian Lynch on Tuesday 14 October 2008
So what you see as the value, CF thinks is a column name.