This is caused by the mechanism we use to efficiently distribute your content within our network. If you wait a few minutes, the files should resynchronize automatically. The exact time depends upon the type of the file and the time since it was last modified. HTML files are checked most frequently, while images, .zip files, and other large static content are checked less frequently.
If you prefer not to wait, you can also help the process along by visiting the modified page yourself and doing a forced reload. For Internet Explorer, this is done with CTRL-Refresh (or CTRL-F5) and with Firefox this is Shift-Reload (Ctrl-Shift-R on Windows, Command-Shift-R on Mac). This will force that page and all related content (images, .js files) to be resynchronized immediately. Since we have a lot of caches and requests are load balanced among them, you may need to do this a few times to get every cache that might answer for your site.
There is a case where if you access the site before the IP addresses are assigned (within the first minute after it's created), you'll get a DNS error. Once that happens, some versions of Internet Explorer will keep returning errors long after the site is created, even if you use a forced refresh. Waiting a few minutes, restarting IE, and sometimes rebooting have all appeared to help this under various circumstances.
There is also a case where, if you edit a file twice in quick succession (i.e. a few minutes apart) and you access the file between the edits, a software bug beyond our control will occasionally cause the old version to get "stuck" and continue to be served from time to time. The way to fix this is to update the file again or simply use the Unix "touch" command to change the timestamp.
If your site is correctly set up but you have not uploaded any content, you should see a "Not Available" message when you access the site, which you should be able to "refresh away" once you have uploaded something.
