Have you also installed the components on the machine with the desktop client? You need to install them on any machine where that has an install of QV Desktop. You can do this with a custom install of the NPrinting server setup file.
As far as the report population issue, have you followed all the guidelines for configurations within the extension object? http://community.vizubi.com/knowledgebase/articles/280390-how-to-use-nprinting-on-demand-extensions-in-qlikv
If so, please check syntax as the reports, tasks, connections, etc. have to appear exactly as they do in the NSQ. They are case sensitive so any inconsistencies in capitalization will result in error.