I'll have a look at your DXDIAG as see what is going on.
I'm sorry your MxO experience hasn't been satisfying.
It hasnt been satifying after soe had tooked mxo....... mxo has potential, but soe has not the players to get a dev team who can get the potential out of it......
Due to lack of profitability SOE had to consolidate servers which meant removing the Europe Server.
Don't complain about ping speed as I'm in Australia, widely reguarded as one of the worst broadband networks in the developed world and I can play fine... because my computer is fast ... because I paid a lot for it. It's tough but welcome to the world of performance gaming.
I have an Athlon4000+ with an 6800GTS Graphiccard and 1gig Ram on an NF3U Board...... everything is running fine...... only mxo isnt running fine.....
As for your error, it looks like a problem with either your RAM or your videoRAM, one of them is probably suffering from old age. Or it could just be a bug in one of the German version drivers.
Unfortunately the best way to fix a problemlike this is a big hastle... Reinstall your computer from scratch.
WoW is telling you it's a DX9 error simply because DX9 is saying that it can't set the video memory options properly. MxO doesn't have such comprehensive error checking. Perhaps if MxO had as many players as WoW then SOE could afford to support Europe better and have more thorough error testing. But it doesn't.
My Ram is from my old computer..... did you had count all soe games together? I think that they would get about the same player count..... but the problem is that the games are different.
I know many, many people all over the world who have no problems running MxO EVER. Unfortunately the problem is with your machine.
I understand that it's frustrating, but abusing people is not going to get you help. It will just make those of us who help other players FOR FREE, angry.
I hadnt abused players who help for free..... I had helped for free too...... I abuse only the tech team who hadnt get my crew back after the crew bug......
The mashine.... I dont want to buy more parts for my mashine..... as I had sayes, I can play what ever I want with it, only mxo makes problems. And I dont want to play a game where I need everey 3-5 months an mashine upgrade. Look at wow.... one reason why so many players play wow is that they CAN play it on their mashines!
If you really need help you may just have to pay a computer specialist to come to your house and fix your computer for you... after all would you get angry like this if you broke your water heater and couldn't fix it yourself. NO. You'd call a plumber.
I have an XaserIII tower.... I have 10 fans in my case, I think thats enough for cooling
And I had build up this mashine for my selfe, I do know what my mashine can and what not and I know computers since my 12th year 
I will do an post what I miss in mxo.... and why I left this game...... so, see you on this post