Web form won't load

[accessible]

I have an Access 2010 web database--very simple, one table, one form, one report--just a suggestion box for employees. It was created as a web db and uploaded to SharePoint 2010 (SharePoint Enterprise, with the latest versions of IIS and SQL). It runs beautifully from inside our company network, but when I try to run it from the internet, it starts SharePoint but then fails to load the very simple input form (please see attachment) with a classically cryptic error message. I've checked all the services and features and everything appears to be set up correctly. Obviously, there's something else that I need to do. Does anyone have any ideas? (BTW, I'm not a network guru nor a programmer, just an Access geek.)

Thanks in advance!

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