Jetreports 2009 on Terminal server 2008R2

Hep, I'm trying to get jetreports 2009 working on a terminal server 2008R2… The problem is that it's only working if the design users are local administrators on the server…. otherwise the "datasource settings" is reporting the error: Navision C/Front client returned this error: "DB_Server_Name\INSTANCE could not be found