your using the wrong session variable in the manage relational table behaviors.
$WA_sessionName = "WADA_Insert_Print";
sets the name of the session as "WADA_Insert_Print".
In the manage relational table behaviors, you are binding to the session named "WADA_Insert_print". Note the lower case p. PHP is case sensitive.
change line 118 to use a lower case p:
$WA_sessionName = "WADA_Insert_print";