This is not a bug.
Um, that "shit", as you so profoundly stated, means that the client program cannot find a particular file or the game installation is corrupted in some way. The latter could be due to a corrupted file that was downloaded and unpacked.
What is the path to your game installation? It should be C:\Program Files\Runes of Magic (32-bit Windows) or C:\Program Files(x86)\Runes of Magic (64-bit Windows). If you've installed the game on a drive other than C:\, you may have problems getting the game to start.
If the noted file is missing, you will need to uninstall the game and reinstall it, along with all the associated patches. If the file is corrupted, you will need to uninstall, delete the installation files, then redownload and reinstall.
Fortunately, there is a new set of installation files available here:
Manual Downloads for the 6.0.1 RoM Client
Read what Inferiority says in the starter message and make sure that you download a copy of
all the files listed, including the ROMSetup.exe file. The number of patches required to bring the game client up to date will be far fewer and you will not need to use the Gameforge Live download manager.
Hope this helps.