I have successfully created a widget for my Facebook profile page, and I even (supposedly) successfully installed it there! But I can't see it.
 
Facebook does not have a Help department, and I already sent a message to the owners of the Greeting Card Seller app on Facebook, but I don't expect a reply. Other Facebook people seem to be having the same problem.  
 
Can GCU's people talk to the people who run the Greeting Card Seller app over on Facebook and get this worked out? I am eager to put up more cards in my shop and start using the widget.
 
Thanks

I had the same issue, so I gave up and just added the www.greetingcarduniverse.com/ etc. line to my personal information that shows up on my Facebook profile.  But then I found out that every time I write a message to someone, up pops the widget and the whole deal.  So apparently it works there.  In fact, it's so prominent, it's almost embarrasing!  (but secretly I think it's really cool) haha  Maybe it shows up to other people but not to us?  Try messaging someone and see if it works.
Robin

To answer your question, I installed it via Greeting Card Universe (they have a page that walks you through the steps and automatically, supposedly, installs it). The only way I know it successfully installed (or so they say) is that in Facebook, it says "you are already using the Greeting Card Seller app". So I can't even try and install it via Facebook.
 
Grr.
 
But I will try that message thing that was suggested here. Thanks!