Topic: device unable to open

I am connecting RPi Uart pins to YHY502CTG rfid module for serial communication. i have disabled the serial console from /boot/cmdline.txt and /etc/inittab to avail te uart for communication. i have installed the libnfc on my board n followed the steps so far..
I am able to get NFC 1 device(s) found.. but the next lines says error about nfc unable to open device.. what is the solution to the prob?