As I mentioned in #lisp on irc I got the mentioned error in cxml-stp/xpath.lisp in normalize-text-nodes! (starts at line 191) when using atdoc with a completely fresh checkout of everything through clbuild. Apparently children is NIL when parsing base-uri.xml.
I got it working again (at least, no error and atdoc seems to produce the correct docs), by changing the following in normalize-text-nodes!:
(when (loop for child across children for a = nil then b for b = (typep ...
into:
(when (and children (loop for child across children for a = nil then b for b = (typep ... )
Don't know if that really fixes the problem, but it got me up and running again...
Gr, Thijs