FSX is not starting anymore after installing patch v2.10 for PMDG 747-400 X

I just installed everything fresh. Fresh Windows XP, with latest service packs, FSX with SP-1 and SP-2. PMDG 747-400 X was running after this. Now I installed the new patch v2.10 and FSX is not starting anymore. When I try to start is I see the default startup screen and then it takes a while and a window pops-up saying 'Ein schwerwiegender Fehler ist aufgetreten' (I hope I translate it correct: 'A severe error occurt'). There I can choos to try again and/or send a error report to Microsoft. But it crashes everytime again.Any ideas how to get it working again? I spend many hours of installing FSX with all addons and I don't want to reinstall everything.Regards,JJ