BACnet can be a bit tricky to integrate but I have had some success with it. I actually created my own subroutines to read/write to a device. I cannot answer the specific question about Nick’s subroutines but I know a few people have used them with success.
Are you attempting to make a PAC controller a device in a BACnet ecosystem? Or are you just trying to read/write data to a BACnet device? I can try to help either way. Feel free to respond here or contact me at firstname.lastname@example.org.