Error while publishing to bi server

hi all,
I am trying to publish reports generated in pentaho report designer to bi server version 4.8 stable...Both of these are open source editions.
However when i go to File->Publish and click on OK it gives an error as " Login to server failed: Could not connect to http server on localhost"
why is this happening?...in the username and password I am keeping the default as it is and then clicking ok...
Is this the correct way or is there some other procedure to follow..
Can anyone please explain the procedure in detail..Its really urgent..Please help me.

Thanks
-Apoorva