My best friend lives in Canada and I just purchased an ebook she really wants to read as a gift for her from Barnes and Noble. However when she tried to download it, it said the book wasn't available in her location and gave her a gift card instead which she most likely won't be able to use either. Has anyone ever had success with sending an ebook internationally? There was nothing that told me I couldn't send the book internationally when I bought it so for both of us it's just been a waste of money.

Barnes and Noble is limited to the US.  You would need to buy from an international bookstore.  Such as Kobo or ARe.  Amazon sells outside the US, But I think you need to be in the country specific website.  (At the bottom of the page.)

IF they gave her the Gift card then she should be able to use it.   IF she cant Contact B&N & Request Your Money Back!  They Can send it back to you!  Been there Done that!

I cannot buy ebooks for anyone outside the US via B&N or Amazon.   Amazon will if you find it on that countries amazon page, and if it is not, you cannot buy it.

If the book is not released in canada, then NO ebook seller will be able to sell her a copy. It's something I've run into with a few YA books. that I wanted my niece to have. 

If the book is not released in canada, then NO ebook seller will be able to sell her a copy.

This.

Many ebooks have geo-restrictions and the publishing rights are sold seperately to different companies in different countries. So ebook stores can't sell them outside the area they've paid the right to service.

An explination Here.

The paper book business has always had the notion of being able to sell the rights of a particular book to different publishers by geographic region. Although we would tend to agree that this notion is outdated in the world of the Internet and eBooks, the fact is those contracts are still in force. If publishers do not take steps to ensure their eBook sales are adhering to the terms of those contracts, they are subject to legal action from whatever other publisher has licensed the rights to the eBook in other countries. Effectively, the publisher's hands are tied. As such, they require us to enforce these restrictions. If we did not obey the publisher's wishes, the publisher would withdraw the eBooks from sale on our web site for all customers.

You can't even go to another country and use your American device to purchase ebooks.  Maybe B&N will give you a refund. Or maybe she can someone how give the gtift card to you and you can use it and get her something else.