AppInventor 2 Internal Error

When I am doing Build of App Inventor program, An internal error has occurred. And, I submitted the bug report. The following message was shown. How can I resolve this problem? The error always even though a simple new project, like show "hello world" text message.

Ooops! We tripped on a Bug!

Please help us by telling us what you were doing at the time this happend. We have already included some technical data with this report. If you do not submit this report, nothing will be reported to us. If you do submit a report, your comments along with the technical data will be sent to us.

Thank you for your help in making MIT App Inventor better!

Technical Data to be Submitted:

notes = Browser: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.99 Safari/537.36
foundIn = nb152a
faultData = com.google.gwt.core.client.JavaScriptException: (TypeError) : Cannot read property 'length' of null
projectId = 5373652082884608

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First make sure that there are no red triangles in your code.
What is the size of your App? How many screens does it have?
Then, try reloading your page or try another browser.
Cheers, Ghica.

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There are no red triangles in my code. And, there is only one screen. Please see the attached screen capture. 

I also tried the HelloPurr, the same Internal Error has occurred.

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What browser are you using?
If Firefox, try Chrome, if Chrome, try firefox.
If Edge or IE, App Inventor cannot run with it. That would be the cause of your problem.
Cheers, Ghica.

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Thanks for reply. I am using both Chrome and Firefox. Both have the same error. 

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Maybe you can post an .aia that has the problem (just to make sure that it is your hard/software and not a strange .aia)
Did you try to build your .apk via a QR-code or by storing it on your PC?

Otherwise, maybe one of the develpoers (Evan?) knows a better question to ask.
Cheers, Ghica.

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Hi Ghica, attached are my .aia files. Both are very simple ones. I tried to build my .apk via a QR-code or by storing it on your PC, all failed. 

Is it due to PC environments issue? 

Thanks,

attached files:

firstApp.aia          HelloPur.aia

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Hi,
I tried both your .aia's and they both built and installed fine. I cannot post the .apk's here because it is against forum policy.
Anyway, it must be something in your PC environment that is strange.

Did you try to run the the AI-companion on a phone with your apps? Did that work? If not, it must be your WIFI. If yes, something strange with your Windows setup. Which version of windows do you have? And do you have administrator rights?
Cheers, Ghica.

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The AI-companion on a phone does work fine. My PC is running Windows 7 and using administrator rights. 

It seems my Windows environments problem. Any suggestion how to figure out the cause.

Thanks,

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