South America - Taca Flights LAX-LIM having trouble booking

Hello,
We are looking for affordable flights from LAX to LIM 12/16-1/7, and have found some decent rates on Cheaptickets.com, Expedia, and Orbitz---cheaper than on other sites and on Taca's website. However, when we click to book, on all these sights an error message pops up saying that due to changes in availability they have having trouble confirming with the airline and to either mke a new selection or try again later. We have been trying for 3 days since Sunday, and still the same deals are listed and the same error message pops up when we try to book. Does anyone have any insights? I am really hoping we can find tickets to Lima, Peru for our dates for less than $3000 or at least not much more.
Thanks!

This is probably a GDS situation where the sites are showing "general availability" vs. "last seat availability." It is a bit complicated, but it occurs when the booking engine doesn't use the same reservation system as the booked airline.

Here's an example.

A travel agency searches generally for availability AAA/BBB
The search comes back
(1) F4A4Y9B9H7M5 etc etc... These are not real time updates. A search via the direct link to the airline's system may come back
(2) F2A0Y9 etc etc - so if you went to book 3 or 4 F seats, it would not be available. It sounds like your cheapest fare is showing as available via the search type (1) that Expedia is performing, but then Taca's website cannot confirm it because the availability doesn't exist (because true inventory is (2)).

That is probably what is happening.

Wow, thank you for that complex detailed explanation! It made some sense, though. It is just frustrating to see affordable tickets and then not be able to purchase them. We are getting the same thing from many of the travel search sites. Hopefully we can find a flight we can afford.

Julibee, if you can be more flexible with your return flight the ticket prices are lower on the weekdays following the 1/7-8 weekend. This is the prime travel season to South America, so flights will be more expensive, and availability limited.