Corrected bug in ATmega168 demo in the RS-485 driver. Also updated the IAR project for Embedded workbench 5.10. Stats:

IAR Atmel AVR C/C++ Compiler V5.10A/W32 
10191 bytes of CODE memory (+36 range fill) 
  775 bytes of DATA memory (+24 absolute) 

avr-gcc (GCC) 4.2.2 (WinAVR 20071221rc1)
Program:   12052 bytes (73.6% Full)
Data:        481 bytes (47.0% Full)

bacnet-stack/ports/atmega168/main.c

@@ -33,6 +33,7 @@
 #include "txbuf.h"
 #include "iam.h"
 #include "device.h"
+#include "av.h"
 
 const char *BACnet_Version = "1.0";