Matlab script error

Why do I get this error?

Version A13 Pro

Code:

clear classes
clear all
srate = 48000;

SYS=target_system('ancTest', 'ANC Test Bed');
add_pin(SYS, 'input', 'mics', 'MIC inputs', new_pin_type(3,96,48000));
add_pin(SYS, 'output','spks', 'Speaker Outputs',new_pin_type(3,96,48000));

add_module(SYS, router_module('Router1',1,3));
SYS.Router1.channelIndex = [0;2;3];

add_module(SYS, periodic_function_gen_module('rpm', 48000, 96));

Error:

Struct contents reference from a non-struct array object.

Error in awe_variable_subsref

Error in awe_module/subsref

Error in periodic_function_gen_module (line 94)
add_variable(M, 'offsetRad', 'float', (M.offset/180)*pi, 'derived', 'Offset in radiuns.', 1);

Error in test (line 13)
add_module(SYS, periodic_function_gen_module('rpm', 48000, 96));