You can buy the disk for EU units here: -
Comand Online Ltd :: Mercedes SatNav/COMAND :: Service Update Disks :: Model Year 01 Firmware Update for COMAND 2.0 & 2.5
If you have a USA unit and he has a EU unit that may explain the missing RDS text.
Don't do firmware updates with copied disks - they are harder for the laser in the CD player to read and more fail to read the disk - and you don't want that to happen during a firmware update.
Richard