That is an error coming while attempting Flickr.com from PC in certain gulf countries like UAE and Iran due to various cultural & religious reason,the Flickr.com has banned some countries from photo sharing to such countries.Government Ban is also applies to such countries by using some social networking websites.
This is not a trick but Mozilla Firefox tricks,If is an Firefox extension to assess Flicker , however you can use the standard proxy route to assess flicker from banned countries but this add on trick is much better than the standard proxy route,The main advantage of this add on is that, there is no configuration, no any setting,You just need to install the Access Flickr extension for Firefox and restart your Mozilla Firefox,You have done.The trick was founded by Iranian photographer who's an ardent Flickr fan himself.
The Access Flickr extension for Firefox contain the HTTP header parameters ,before sending a request to Flickr and therefore fools the government filters. This extension is only useful for accessing Flickr.com, it won't work for other sites like YouTube or Orkut.and other banned social networking websites.
Download Access Flickr | Hamed Saber on Flickr
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