alice-teacher Error with dummy objects in Alice 2

[EMILY REED]

My students are working on the Treasure Hunt tutorial where they learn about scene changes.  One student missed the step where it has you drop a dummy object at the camera and is now trying to go back and fix it.  When he tries to add it in, he's getting an error message saying there is already an object in the world named Dummy Object, but we can't find anything like that in his object tree.  
 
Does anyone have a solution or suggestion?  I hate to see him have to start over as he's already worked on it for two days.  
 
I'm attaching his world to this e-mail.  
 
Thanks in advance,
 

Emily Reed
Business Teacher, Collinsville High School
 
 
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