worked fine on trial
After I paid and installed the serial (Auto on GVA and manually in ZRH) that is when everything started
now the fsx crashes ....
Sorry, but that's just not possible. There's no difference whatsoever in the program between Trial and Full version, nothing in the program changes, at all.
If it worked fine in the Trial, than the problem is caused by something else, and the fact that happened after you purchased the sceneries, is just a coincidence.
BTW, do you have the Error Signature details about which module has crashed, as I've asked in the previous message ?