[SR-Users] function get_user_group: parameter 1 is not constant

I'm getting following config error when i use the api from group module. CSBC-JJ:/srv/www/htdocs/core # /usr/sbin/kamailio -c -f /etc/kamailio/kamailio.cfg loading modules under /usr/lib/kamailio/modules_k/:/usr/lib/kamailio/modules/ 0(5020) : <core> [cfg.y:3412]: parse error in config file /etc/kamailio/kamailio.cfg, line 455, column 20-36: function get_user_group: parameter 1 is not constant 0(5020) : <core> [cfg.y:3415]: parse error in config file /etc/kamailio/kamailio.cfg, line 455, column 48: bad command 0(5020) INFO: pv [pv_shv.c:61]: locks array size 16 ERROR: bad config file (2 errors) I have used the API get_user_group as shown below $avp(r_contact)=$ru; $avp(temp)=$null; get_user_group($avp(reg_contact),$avp(temp)); xlog("L_ERR", "request - M=$rm get_user_group=$avp(temp)\n\n"); Please let me know what could be reason for this error. Thanks Jijo