Can't Open Alice World - "IllegalNameValueException"

[Habstinat]

Here is the error in question, which I recieve after attempting to open the world:

Unable to load world




Alice version: 2.2  09/10/2010



Throwable that caused the error:

edu.cmu.cs.stage3.alice.core.IllegalNameValueException: Unfortunately, something else in this world is already named "index," so you can't use that name here.

	at edu.cmu.cs.stage3.alice.core.Element.checkForNameCollision(Element.java:218)

	at edu.cmu.cs.stage3.alice.core.Element.internalSetParent(Element.java:677)

	at edu.cmu.cs.stage3.alice.core.Element.insertChildAt(Element.java:1047)

	at edu.cmu.cs.stage3.alice.core.Element.addChild(Element.java:1055)

	at edu.cmu.cs.stage3.alice.core.Element.setParent(Element.java:638)

	at edu.cmu.cs.stage3.alice.core.response.LoopNInOrder.loadCompleted(LoopNInOrder.java:59)

	at edu.cmu.cs.stage3.alice.core.Element.loadCompleted(Element.java:1426)

	at edu.cmu.cs.stage3.alice.core.Element.loadCompleted(Element.java:1426)

	at edu.cmu.cs.stage3.alice.core.Element.loadCompleted(Element.java:1426)

	at edu.cmu.cs.stage3.alice.core.Element.loadCompleted(Element.java:1426)

	at edu.cmu.cs.stage3.alice.core.Element.loadCompleted(Element.java:1426)

	at edu.cmu.cs.stage3.alice.core.Element.loadCompleted(Element.java:1426)

	at edu.cmu.cs.stage3.alice.core.Element.loadCompleted(Element.java:1426)

	at edu.cmu.cs.stage3.alice.core.Element.load(Element.java:1551)

	at edu.cmu.cs.stage3.alice.authoringtool.dialog.LoadElementProgressPane.construct(LoadElementProgressPane.java:37)

	at edu.cmu.cs.stage3.progress.ProgressPane$2.run(ProgressPane.java:84)

	at java.lang.Thread.run(Unknown Source)

The world is fairly simple and seemed to have saved without error the last time I opened it. The world file is attatched to this post. Any ideas as to why this is happening or what I could do to fix this? Thanks in advance for any help.