Sometimes things break... including websites.
As technology evolves and customers want more features from websites, updates (some minor / some major) are needed, and unfortunately sometimes adding one feature has unintended consequences. There is usually quite a bit of QA testing that goes on, but as each person uses a website slightly differently, it's nearly impossible to account for every possible scenario before releasing an update.
I can assure you that PRICELINE / HOTWIRE both want to sell you a hotel room, make it as easy as possible to book, and have the overall purchase experience be positive. It may take a few days for them to get around to it, but now that they are aware of the issue i'm sure it will be fixed soon.
Hope you're enjoying the weekend away from home.