diff --git a/bacnet-stack/demo/readfile/Makefile b/bacnet-stack/demo/readfile/Makefile
index 41fda9e8..db1b48fa 100644
--- a/bacnet-stack/demo/readfile/Makefile
+++ b/bacnet-stack/demo/readfile/Makefile
@@ -20,7 +20,7 @@ BACNET_LIB_DIR = ../../lib
 BACNET_LIB_NAME = bacnet
 BACNET_LIB_TARGET = $(BACNET_LIB_DIR)/lib$(BACNET_LIB_NAME).a
 # Compiler Setup
-INCLUDES = -I$(BACNET_INCLUDE) -I$(BACNET_PORT)
+INCLUDES = -I$(BACNET_INCLUDE) -I$(BACNET_PORT_DIR)
 LIBRARIES=-lc,-lgcc,-lm,-L=$(BACNET_LIB_DIR),-l$(BACNET_LIB_NAME)
 CFLAGS = -Wall -g $(INCLUDES) $(DEFINES)
 LFLAGS = -Wl,-Map=$(TARGET).map,$(LIBRARIES)