I try to upload a file into the DataStore but i got this http error :
The requested URL is : http://demo.ckan.org/dataset/72dba89d-c320-42b2-8733-5c5084f1213c/resource/4da87da1-755f-410b-9414-936d3c4edd9b/download/data.csv
But when i replace demo.ckan.org with the Ip adresse of my ckan machine i got the file.
Regards.
That would in general mean that DNS is not working as far as CKAN is concerned. Have you tried "ping demo.ckan.org" on the shell of the machine running CKAN?