Hi,
It sounds like you have the new RoHS units, the new S90’s and a different mother board and you will need a new image for these.
Have a look at the model number on the base of the unit, the new units have a “L” at the end. My guess is the old ones do not.
If you are running Rapport 4.4.1 patch the server up with all the patches on this site then download the latest S90 image from wyse.com and create a new image,
Cheers,
-TT