[Serusers] nathelper module

Hi, Firstly I'm quite new to ser... I am trying to use the nathelper.so module with portaone rtpproxy. I have the latest ser release 0.8.12 installed from rpm on red hat 9. I get pass: loadmodule "/usr/lib/ser/modules/nathelper.so" and: modparam("registrar", "nat_flag", 6) modparam("nathelper", "natping_interval", 30) ...uptill here everything is OK however when I also add: modparam("nathelper", "ping_nated_only", 1) I get: Starting ser: ERROR: bad config file (1 errors) I also get the same error when trying to use the nat_uac_test function. Can anyone help me out ? Am I missing something ? Any help greatly appreciated.... Thanks, Dave