I just posted this info in response to a message on another thread, but thought I'd add it here, too, in case it helps someone who finds this thread while searching for info on the same problem:
Booking via another country's website was impossible for me online. I'm American, and I tried various English-speaking countries' websites where I could pay in Euros, as their price when converted to US dollars was better than the price on the US website. (The UK price was worse than the US price, so I did not try them, btw.)
I called my credit card company to check for a fraud block and it wasn't that, and I could also buy other things online from Paris in Euros with the card. So this was definitely an issue specific to the
Disneyland Paris website for other countries. I tried Ireland's website, Iceland's, Canada's, etc. I cleared my browser's cookies each time. None of them would let me book the ressie with my Visa credit card. I then searched tricks online and saw one about doing this by leaving the foreign country name as it was on your contact info, but typing in the rest of your American address in the address line. Tried that, and it also didn't work. So impossible online. I tried for days.
In the FAQ section of the Disneyland website, I noticed that it said it was fine to call and book an offer from another country's website (confirmation info will be delivered in that country's language, so choose carefully). So this morning I had WDW transfer a call to Disneyland Paris, and I told them that even though I'm an American, I wanted to book the deal offered through Ireland's website, which they were happy to do. I paid in full in Euros using the same card that never worked online. No problems at all, and the adjusted price in US dollars was a savings of about $300 over what I would have paid for the exact same package via the USA website (which was still a good deal, as it is a "book 4 nights for the price of 2 nights" offer). So the savings were worth the hassle.
Hooray!
