The "Error 404" is, of course, a reference to the code that Internet users get when accessing a site that doesn't work. A $5 donation to the National Republican Senatorial Committee gets you one of these. "Your contribution fuels our fight to build a Republican majority in the Senate in 2014, which is absolutely critical if we want to repeal and replace Obamacare."
Just don't everyone go at once. That'd crash the NRSC site, and boy, would that be embarrassing.
- bumper stickers