ds is denying your machine from connecting to the server....
for some reason it has decided that that specific machine is not allowed to communicate with the ds server.
you have to open the ds database... i cannot remember the exact table... but it was some thing to the affect of "denied access"... i cannot remember but you will know which table it is when you see it.
anyway in that table you will see all machines that have been denied access; delete the entries and the machine will communicate with the server again.
there is an article on the issue, i tried to search the knowledge base for your but could not find it this time... if you search a bit longer i'm sure you'll find it.
i know this sorted my issue out, there could be more issues but with this one all you have to do is check that that table is clean.... if you machine is in that table, then that's your issue...
oh yes.. check your licenses :-)