You have to use the correct moc to your headers. When you install Qt you must also install the devel tools for this specific Qt versions. And you should fix your buildsystem to call moc. Those moc files do no belong to the sources.

Hello, I just received the "crash report" from our customer! Well, you know what, the app actually did not crash at all, it just showed the cyrillic characters that are known from the qt bug which has been solved in 5.5. Sorry to have bothered you with that nonsense, and thanks for your input and your time! best wishes Manfred