[Serusers] call hunt

i am tring to implement call hunt in ser 0.8.12 (no avpops). there is one problem. i am using exec_dset in the failure route as follows. failure_route[1] { exec_dset("/etc/ser/getnextnumber1 $SIP_OUSER; echo>/dev/null;"); append_branch(); t_on_failure("1"); xlog("L_ERR", "time [%Tf] method <%rm> r-uri <%ru> <%tu>\n"); t_relay(); } after the first failure, the SER sends 408 to the UA (caller) and it gets a busy tone. at this point, the second number of the call hunt group is ringing. but no voice can go through as the caller UA is showing 408 Request Timeout. please help, regards, tulika