diff --git a/make-includes/build_lecture_rules.make b/make-includes/build_lecture_rules.make
index ee2de8c..9cd2856 100755
--- a/make-includes/build_lecture_rules.make
+++ b/make-includes/build_lecture_rules.make
@@ -239,7 +239,7 @@
 ################################################################################
 #
 # Install the appropriate files on the web server. This relies on the
-# environment variable HANDBOOK_INSTALL_DIRECTORY being defined, and
+# environment variable HANDBOOK_INSTALL_ROOT being defined, and
 # (assuming that this variable points to a directory on the network) the
 # appropriate share has been mounted.
 #