now that this contest is over I want to do another one
See the answer by disco on this stackoverflow page for how to configure your app settings to fix that error: Canvas URL / Secure Canvas URL error message
You need to host the game outside of Facebook (on your own website), Facebook won't host it for you. It just puts it in an iframe for you.
Put on the last touches and finally got my game uploaded. Hopefully it's submitted in time, it's still April 30th where I live :).
Here is the link:
Spooky Kitties
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Click the "Reset dialogs" button in the preferences dialog. <img src="http://www.scirra.com/images/articles/preferences-page1.png" border="0">
Click the "Reset dialogs" button in the preferences dialog.
<img src="http://www.scirra.com/images/articles/preferences-page1.png" border="0">
Worked for me, thank you
Member since 23 Jan, 2013