Index: /trunk/doc/manual/Makefile.kmk
===================================================================
--- /trunk/doc/manual/Makefile.kmk	(revision 68399)
+++ /trunk/doc/manual/Makefile.kmk	(revision 68400)
@@ -712,5 +712,5 @@
 	$(QUIET)$(RM) -f $(addprefix $(@D/),$(VBOX_SDKREF_LATEX_FILES_TARGET))
 ##      check it for validity first.
-#ifdef VBOX_HAVE_XMLLINT
+#if defined(VBOX_HAVE_XMLLINT) && defined(VBOX_PATH_DOCBOOK_DTD)
 #	$(QUIET)$(VBOX_XMLLINT_WITH_CAT) --dtdvalid $(VBOX_PATH_DOCBOOK_DTD)/docbookx.dtd $<
 #endif
@@ -763,5 +763,5 @@
 	$(QUIET)$(RM) -f $(addprefix $(@D/),$(VBOX_ACCESSIBILITY_LATEX_FILES_TARGET))
 #	check it for validity first.
-ifdef VBOX_HAVE_XMLLINT
+if defined(VBOX_HAVE_XMLLINT) && defined(VBOX_PATH_DOCBOOK_DTD)
 	$(QUIET)$(VBOX_XMLLINT_WITH_CAT) --dtdvalid $(VBOX_PATH_DOCBOOK_DTD)/docbookx.dtd $<
 endif