.NET 3.5 needed to run an application using the Studio 2015 API?

Hello,
We are programming a standalone application to check sdlxliff files, using the parser of Studio2015 by implementing the FileTypeManager. Everything works pretty well and also on many different Computers and Servers. But on the productive machine, running with Windows Server 2012 R2, we get this error:

ERROR: Ein Aufrufziel hat einen Ausnahmefehler verursacht.

   bei System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)
   bei System.Reflection.RuntimeConstructorInfo.Invoke(BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   bei System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes, StackCrawlMark& stackMark)
   bei System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes)
   bei System.Reflection.Assembly.CreateInstance(String typeName, Boolean ignoreCase, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes)
   bei Sdl.FileTypeSupport.Framework.Core.Utilities.IntegrationApi.DefaultFileTypeManager.CreateInstance(Boolean autoLoadFileTypes)
   bei Check.Checker.Checken(String einstellungsdokumentFilePath, String dateiBerichtFilePath, String sdlxliffFilePath, MyLogger logger) in Checker.cs:Zeile 40.
   bei Check.Program.Main(String[] args) in Program.cs:Zeile 135.

I generally get this message when the compiled exe file is not in Studio4 folder, but in this case, the file is at the right place. We also get a pop-up windows advising to install .NET 3.5 but our programm uses .NET 4.5.2. and I thought Studio2015 as well. Are there any dependencies with .NET 3.5?

Kind regards
Sébastien Desautel