The @SPTABLERNDV is used to associate random variables with an instance of a discrete outcome table.  The format of @SPTABLERNDV is:

@SPTABLERNDV( 'DIST_INSTANCE_NAME',  RANDOM_VAR_1[, ... , RANDOM_VAR_N]);

Please check to see that the arguments conform to this syntax.  For more information on defining outcome tables and using @SPTABLERNDV, please refer to the Declaring Outcome Tables section of Chapter 14.