What Yrcanos said.
Additionally, the Softpedia link for "their" RoM game client is unofficial and we (Gameforge) cannot support it. The newest (currently) set of installation files are the 5.0.5 files that can be downloaded from either the US or EU websites, or from the links in Inferiority's thread. Even the mirror sites that can be found on the EU RoM website have the older 5.0.0 installation files.
And, sad to say, there's no ETA on when an updated 6.0.0 set of installation files will be available.