Hi,
I bought the game here to be able to use the community patch (I already have the german version of the game, which starts without a problem), but when I start up the game it gets stuck in the "Loading Arcanum" Screen and I have to kill it via the Task Manager.
I tried reinstalling it without the community patch, but it doesn't make a difference.
My system specs:
Windows XP SP3
Amd Phenom II X4 955
3,25 GB Ram DDR-2 800
Radeon 4890 Vapor-X 1GB
Well, I hope you can help me.
As I said, it's extremely strange since the german version runs like a charm (aside from the missing community patch, of course).
Thanks in advance for your help.

Have you added the -no3D annd -doublebuffer switches to the game shortcut, that usually clears up most graphics problems. See attached image for adding the switches info. . . =)

Unfortunately this didn't help either :/

I'm not sure if you are running the HR mod but uninstalling it completely or trying different resolutions can cure some graphics problems. Go to the Arcanum directory and find the HighRes.bat to uninstall or set different resolutions
Also, look at this thread for info on a program that sets infinity to a single core. Might try doing it manually first rather than using RunFirst.
You can do it manually by starting the game, ALT-Tab to the desktop, open task manager (CTRL - ALT - DEL ), find the [game name].exe on the Processes tab, right click the exe and click Set affinity . . . on the resulting dialog. Un-check all but the CPU 0 check box. Close the task manager and play the game. If this helps I suggest using RunFirst as it sets the affinity for the game without having to go thru the task manager process each time you play. See attached image
Also, look at the GOG support page for Arcanum.