Invalid Schema/DTD file

When opening Arbortext Editor 5.3 M020, this message appears:

Dialog title: Invalid Schema/DTD file.

Dialog text: [A15001] Unable to load document type due to errors parsing XML schema: + file path of the schema file (xliff.xsd). Choose: 1) Browse for Schema/DTD; 2) Open in free-form mode without Schema/DTD; 3) Open as text

If option 1 is chosen, the same message is shown again and again even after having browsed for the xliff.xsd file.

If option 2 is chosen, Arbortext Editor opens, but some functionalities don’t work: preferences window doesn’t show, it’s impossible to insert tables or notes, and so on. Oddly, documents are normally validated.

In arbortext.wcf file the Entities and Doctypes repositories are well addressed. It seems Arbortext Editor sees DTDs, so I don’t understand why the error message appears and why some functions don’t work. I’ve already uninstalled and reinstalled the program, without any results. Any idea?

Sonia