Hmmmm…
If I do like Wim says (over), i.e. remove the pointers to clientraw files in wdlconfig (in wddata directory), the WDL actually starts and works from “inside”; starting it from index.html in the wddata directory. Strangely it seems that if I restore the wdlconfig (with the pointers), and then try to start, WDL returns same error message.
…hmmmm