I think that you should send the file to Igor. You're entitled to support.
Perhaps you should create a ticket. I don't know how things are handled nowadays.
Perhaps both your client and CT are right if this is a sdlppx project (not a single sdlxliff file)? The sdlppx project my have the target language set but the sdlxliff file(s) inside the project may still have the target language missing. Just tell your client to presegment and possibly pretranslate the project in Trados, and then you should be able to edit it in CafeTran.
A client of mine just sent me an SDLXLIFF file, but CT won't open it because it says that the target language is missing, the client (with Trados Studio) says the target language is there, who's right?
Thanks and cheers,