SAP GUI doesn't start from Eclipse ABAP

The following exception occurs, when i start an ABAP program from eclipse:

java.lang.IllegalStateException: Could not start SAP GUI for Windows: "C:\Program Files (x86)\SAP\FrontEnd\SAPgui\SapGuiServer.exe at com.sap.adt.sapgui.ui.internal.win32.embedding.WinGuiServerProxy$SapGuiServerProcess.start(WinGuiServerProxy.java:550) at com.sap.adt.sapgui.ui.internal.win32.embedding.WinGuiServerProxy.startGuiServerProcess(WinGuiServerProxy.java:161) at com.sap.adt.sapgui.ui.internal.win32.WinGuiFragment.getGuiServerProxy(WinGuiFragment.java:85) at com.sap.adt.sapgui.ui.internal.win32.embedding.EmbeddedWinGuiEditor.createEmbeddedGuiContent(EmbeddedWinGuiEditor.java:80) at com.sap.adt.sapgui.ui.internal.views.AbstractSapGuiWorkbenchPart.createPartControl(AbstractSapGuiWorkbenchPart.java:124) at org.eclipse.ui.internal.e4.compatibility.CompatibilityPart.createPartControl(CompatibilityPart.java:154) at org.eclipse.ui.internal.e4.compatibility.CompatibilityEditor.createPartControl(CompatibilityEditor.java:96) at org.eclipse.ui.internal.e4.compatibility.CompatibilityPart.create(CompatibilityPart.java:361) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:567) at org.eclipse.e4.core.internal.di.MethodRequestor.execute(MethodRequestor.java:58) at org.eclipse.e4.core.internal.di.InjectorImpl.processAnnotated(InjectorImpl.java:998) at org.eclipse.e4.core.internal.di.InjectorImpl.processAnnotated(InjectorImpl.java:963) at org.eclipse.e4.core.internal.di.InjectorImpl.internalInject(InjectorImpl.java:139) at org.eclipse.e4.core.internal.di.InjectorImpl.internalMake(InjectorImpl.java:408) at org.eclipse.e4.core.internal.di.InjectorImpl.make(InjectorImpl.java:331) at org.eclipse.e4.core.contexts.ContextInjectionFactory.make(ContextInjectionFactory.java:202)

I have currently Eclipse 2019-09 with SAP GUI 7.6 patch level 3. I have also tried several other versions (7.5 7.4 with various patch levels), always the same result. SAP GUI is installed in C:\Program Files (x86)\SAP\FrontEnd\SapGui.

It's really frustrating, i tried to re-install everything, always the same result. Can anyone help please?

thanks in advance!

regards,

Thomas