Xwem cannot be compiled under MS Windows because x-emacs-application-class
is not defined. Loading xwem-minibuffer does this:
;;;; On-load actions:
;; Define application
(add-to-list 'xwem-applications-alist
`("xemacs-xwem-minibuffer"
(and (class-name ,(concat "^" x-emacs-application-class
"$"))
(class-inst ,(concat "^" xwem-minibuffer-name
"$")))))
And xwem-main does (require 'xwem-minibuffer).