Did you mean to do something like the following instead:
@create Dice
&CMD_ at ROLL_MOD Dice=$@roll
*d*+*:[setq(2,die(%0,%1))][setq(3,add(%q2,%2))];@switch
eq(%q2,mul(%0,%1))=1,{@pemit %#=%[Dice %0D%1+%2:%] %q3
%ch%crNatural!!!},{@pemit %#=%[Dice %0D%1+%2:%] %q3}
@lock Dice==me
@set Dice=COMMANDS
drop Dice
Brazil