If they simply need to run the file they will some level of use of CR. If they can run CR from their workstation then all you have to do is put them on the server, make sure they are able to connect to the data (how that is done will depend on how you set that part of the report up), and make sure the users have the necessary network permissions the server.
However, if your users dont have access to CR you will have to find a way to do that. That is where the windows forms or web access question came from. It would be like trying to open an Excel file if you dont have Excel. Perhaps Brian or others may chime in with comments.
Regards,
John W.