It's just loaded fine for me, though obviously I didn't try to make a booking or anything. The usual advice applies: try it in Troubleshooting Mode — press Alt-H and choose it from the drop-down menu that appears. If it works then it's likely a problem with some personalised setting of yours or an extension you normally use. You haven't said what operating system you use; I'm on Linux and the problem may only effect Windows or Macs. Anti-virus software could also be causing problems.