Sorry, Vituali, its still no go. I have downloaded the direct links and I still get the same result. I don't know for sure where the Aerosoft file came from, but I guess that it was their version of London City, which I uninstalled ages ago. Anyway, it isn't removed when you answer yes to the remove question in the uninstaller. The German Wings file is removed.
I think that I have had the same experience that most of the others have had. My first airport was Geneva and I had the problem with that product. Then I followed the advice given on this forum and all was fine for a while. I added further airports and everything was still fine. Then suddenly I began to get the dll warning message again and FSX shut down, but again after uninstalling and then re-installing Geneva the problem went away. Now it is some weeks ago that it has returned again, and I tried to repair by uninstalling JFK and then re-installing it, but to no avail. Since then I have simply answered no to the dll question and the sim runs well.
I accept that the cause is probably some other addon on my system, although the only dll files I have, apart from the default and FSDF files are for PMDG, LDS and FSUIPC. I do have aicarriers in the exe.dll file, but that also has been there for some time. I don't think that it is related to Win7 I beta tested the original betas and also the pre-release and I didn't have a problem then. It could be an update since, I don't know.
I do not want to waste any more of your time, and I thank you for the help you have given. I know from experience with UK2000 how difficult it can be to track down a problem on a users system via the forum. I will continue to monitor this thread in the hope that something else may show up.
Norman