I managed to solve it. I did check my installed versions of Visual C++ and I had a comparable set of both x64 and x86 libraries to your setup. I tried installing them again from the Microsoft website, but still the same error. I then looked at the properties of the Start_as_program.exe icon. In the section for compatability, I ticked "run this program in compatibility for :" and selected "Windows 7". It now works The uniserver control panel child windows now function correctly. So, I can check server status, etc. Not sure why the changing of compatibility mode had that effect ? D.