TC_FF: evalXPath - TypeError: Ident.constructors.JavaScript.createIdentJSSandbox is not a function

http://h30499.www3.hp.com/t5/LoadRunner-Support-Forum/TC-FF-evalXPath-will-not-evaluate-variable-inside-of-for-loop/m-p/6549046#M10181

The above link references how I use evalXPath. The solution I have worked brilliantly in TC for FF in LR 12.00, but now in 12.01.2079.0, this step no longer works.

The error from mdrv.log shows the progress, the correct evaluation of the variable, and the subsequent failure:

Notify: Transaction "004 Show 500 Contacts" ended with "Pass" status (Duration: 0.5819).
t=00027511ms: ** 9: For (var i = 2; i < 21; i++) ** started    [MsgId: MMSG-205180]
t=00027535ms: ** 9: For loop 1 ** started    [MsgId: MMSG-205180]
Notify: Transaction "005 Open Contacts Page" started.
t=00027859ms: ** 9.1: Click on i javascript_link ** started    [MsgId: MMSG-205180]
t=00027867ms: Error -205177: TypeError: Ident.constructors.JavaScript.createIdentJSSandbox is not a function
Ident.constructors.JavaScript.prototype<._evaluate@chrome://truclientrre/content/ident/IdentJavaScript.js:13:1
find@chrome://truclientrre/content/ident/Ident.js:274:1
Ident.prototype._evaluateImpl@chrome://truclientrre/content/ident/Ident.js:381:3
Ident.prototype.evaluate@chrome://truclientrre/content/ident/Ident.js:168:1
TestObject.prototype.evaluate@chrome://truclientrre/content/model/TestObject.js:391:3
.evaluateTestObject@chrome://truclientrre/content/model/TestObjectDelegator.js:52:1
@chrome://truclientrre/content/model/Step.js:1261:4
window.RuleEngine.dispatch@chrome://truclientrre/content/infra/RuleEngine.js:111:11
window.Event@chrome://truclientrre/content/infra/Event.js:13:20
.dispatch@chrome://truclientrre/content/infra/Event.js:24:4
.updateReadyState@chrome://truclientrre/content/model/CommonTestObjectStepExts.js:158:1
processStep@chrome://truclientrre/content/model/Step.js:1152:4
processNextStep@chrome://truclientrre/content/model/Step.js:1174:6
enterDispatchLoop@chrome://truclientrre/content/model/Step.js:1209:5
Step.prototype<.start@chrome://truclientrre/content/model/Step.js:481:5
Step.prototype<.delegateRun@chrome://truclientrre/content/model/Step.js:761:5
runAlt@chrome://truclientrre/content/model/StepExts.js:145:14
.callAsync/<@chrome://truclientrre/content/infra/StdClasses.js:44:37
receiveMessage@chrome://truclientrre/content/infra/Utils.js:21:6
.send@https://plta2perf032.infusiontest.com/js/sink_jq.jsp?b=1.36.0.31:13604:6
.ajax@https://plta2perf032.infusiontest.com/js/sink_jq.jsp?b=1.36.0.31:13034:5
ajaxFill@https://plta2perf032.infusiontest.com/js/sink_jq.jsp?b=1.36.0.31:39048:1
ajaxFillDiv@https://plta2perf032.infusiontest.com/js/sink_jq.jsp?b=1.36.0.31:39408:1
submitGrid@https://plta2perf032.infusiontest.com/js/sink_jq.jsp?b=1.36.0.31:39749:5
changePerPage@https://plta2perf032.infusiontest.com/js/sink_jq.jsp?b=1.36.0.31:39700:4
onchange@https://plta2perf032.infusiontest.com/app/nav/link?navSystem=nav.mynav&navModule=contact:1:1
sendMouseEvent/send/<@chrome://truclientrre/content/infra/Mouse.js:35:5
window.Utils.hookTimers@chrome://truclientrre/content/infra/Utils.js:182:45
send@chrome://truclientrre/content/infra/Mouse.js:33:3
.callAsync/<@chrome://truclientrre/content/infra/StdClasses.js:44:37
receiveMessage@chrome://truclientrre/content/infra/Utils.js:21:6

While calling handlers in RuleEngine dispatch, event=[Event type="agent/evaluate-test-object" target="[object ChromeWindow]"], handler=
function (args) {
"use strict";

			Step.evaluateTestObject(args/*identProfile, stepTestObj, callback*/)
	}       Snapshot Info [MSH 1 0]    [MsgId: MERR-205177]
t=02471649ms: ** 9.1: Click on i javascript_link ** was stopped    [MsgId: MMSG-205180]
Notify: Transaction "005 Open Contacts Page" ended with "Pass" status (Duration: 2443.8004).
t=02471716ms: ** 9: For (var i = 2; i < 21; i++) ** was stopped    [MsgId: MMSG-205180]