I have ArGIS Destop 10.2 licenses, and i need to install on server. But server is ot having internet, so in order to generate ecp file, i generated authorization.txt in other machine and uploaded to https://service.esri.com/drm and given me a ecp file but when i copied this to server and tried to authorize licenses. It is giving an error "There were no valid features selected in file."
ECP file is for authorizing ArcGIS Server, not ArcGIS Desktop.
Do you have license codes for ArcGIS Desktop?
Moreover the error message suggests that you have used/activated all the licenses.
Do you have Single Use (SU) License or Concurrent Use (CU) License? If SU, then authorization has to be done using ArcGIS Administrator. If CU, then authorization has to be done using License Server Administrator (License Manager).