Strange Client Includes Issue

Hi!  I have a Script Include, see below.  I have a client script on a catalog form where I can type something in a text field and the text will be sent to the script include for querying.  It shows "unhandled exception in GlidesAjax" error. But what's strange is, as you can see when I do gs.log and check the system log, I do see the searchTerm is expected. 

If I hardcode the line below

searchTerm = this.getParameter('sysparm_searchTerm');

to 

searchTerm = "test", it works.  I'm so confused why the getParameter would give an error. I also copied the client script below.

Client Includes

var GetGrcEntitiesGlobal = Class.create();
GetGrcEntitiesGlobal.prototype = Object.extendsObject(global.AbstractAjaxProcessor, {
    getEntities: function(searchTerm) {
        if (!searchTerm) {
            searchTerm = this.getParameter('sysparm_searchTerm');
            gs.log('GetGrcEntitiesGlobal called with searchTerm: ' + searchTerm);
        }

        var entities = [];

        if (!searchTerm || searchTerm.length < 3) {
            return global.JSON.stringify(entities);
        }

        var grcEntityGR = new GlideRecord('sn_grc_profile');
        grcEntityGR.addActiveQuery();
        grcEntityGR.addQuery('name', 'CONTAINS', searchTerm); // Filter based on the search term
        grcEntityGR.query();

        while (grcEntityGR.next()) {
            entities.push({
                sys_id: grcEntityGR.getValue('sys_id'),
                name: grcEntityGR.getValue('name')
            });
        }

        var result = global.JSON.stringify(entities);
        return result;
    },

    type: 'GetGrcEntitiesGlobal'
});

Client Script

function onChange(control, oldValue, newValue, isLoading, isTemplate) {

    if (isLoading || newValue.length < 3) {
        return;
    }
    var grcEntityField = g_form.getControl('ci_reference');

    if (grcEntityField) {
        var ga = new GlideAjax('global.GetGrcEntitiesGlobal');
        ga.addParam('sysparm_name', 'getEntities');
        var search_term = newValue.toString();
        ga.addParam('sysparm_searchTerm', search_term);
        ga.getXMLAnswer(function(response) {
            var entities = JSON.parse(response);

            grcEntityField.innerHTML = '';
            g_form.addOption('ci_reference', '', '-- Select a Profile After Search --');

            for (var i = 0; i < entities.length; i++) {
                g_form.addOption('ci_reference', entities[i].sys_id, entities[i].name);
            }
        });
    }
}