Cannot access extensions

[Liss]

Hi!  I get this message from the "Manage Extensions" page:

The CiviCRM public extensions directory at http://civicrm.org/extdir/ver=4.2.16|cms=WordPress could not be contacted - please check your webserver can make external HTTP requests or contact CiviCRM team on CiviCRM forum.

Underneath the description of what the page allows you to do is this message:

There are no local or publicly available extensions to display. Please click "Refresh" to update information about available extensions.

When I hit the refresh button the top message goes away and the bottom one remains.

I've set the path in Directories and Resource URLs, and also uploaded an unzipped extension directly to the folder.  Any suggestions? 

Thanks in advance!

[JoeMurray]

Could this have been a temporary error in accessing http://civicrm.org/extdir/ver=4.2.16 ? Occassionally the site is down.