QT Installer Framework Wizard buttons missing

Hi all,

i managed to get an installer running on my machine.

On my machine i used:
1.) The online installer for Windows for QT (https://www.qt.io/download-qt-instal...2-bfb62735f3e5) (QTCreator 4.5.1 and QT5.10.1)
2.) https://download.qt.io/official_rele...amework/3.0.6/[QtInstallerFramework-win-x86.exe|https://download.qt.io/official_rele...k-win-x86.exe]

So i started to modify online example and it´s running fine on my machine.

Now i tried it on a Server pc (no QT installed) and the Buttons in the wizard are missing (see Picture)


So what can I do?
Have I forgot any property?Attachment 13064Attachment 13065