Hey Greg, thanks for your help!!
But I still get the same error message:
Cannot find the script or external object that implements prefix ‘IWObjektImport’.
It`s like he doesnt recognize the custoum extension xml file:
<ExtensionObjects>
<ExtensionObject Namespace=”http://immowelt.de/Import/ObjektImport” AssemblyName=”IWImportAssembly, XSLT_External_Assembly, Version=1.0.0.0, Culture=neutral, PublicKeyToken=c5b7d5a4522ce583″ ClassName=”IWImportAssembly.IWObjektImport”/>
</ExtensionObjects>
I tried everything you guys told me to do. I`m stuck.