Creation of a Sort Set

[Gladiator66]

I am having trouble getting a new sort set to work. This is the first time that I have tried to create a sort set. I added the sort set to an existing 1st file that originally only contained sources. However, after I saved the change to the 1st and performing a quick reload, I received the following error when testing.:

Syntax error in 'eval' script on line 14
-> Non-existent sortset 'HightoLow' referenced by script.

The code added at the bottom of the the 1st File is as follows:

<sortset
id="HightoLow"
name="Longest range first">
<sortkey isfield="yes" id="abValue" isascend="no"/>
<sortkey isfield="no" id="_Name_"/>
</sortset>

Let me know if you have any thought regarding what I may be missing. Thanks.