When you are using Safenet Licensing and see in red letters at the bottom of the licensing tab in License Management System: Note: Using LSFORCEHOST for server list. (see attached LSFORCEHOST.png). This can cause an issue with Rumba on a Citrix box when you install the License Management System in a different location then the LSFORCEHOST environment variable is pointing to. This will cause your Mainframe or AS400 Display for example to return an error that like: AS-400-display is not supported in the installed application.
The reason is that the LSFORCEHOST environment variable takes precedence over the actual license management system location.

To solve this you can either install the License management systme in the same location as this variable is pointing to or remove it through 'my computer' > properties > Advanced System Settings > Environment Variables. For an example you can look at this URL: http://www.itechtalk.com/thread3595.html .