Summing problem



Hello everyone,

I have a problem with maxima when using sums:

----------------

Mult2(Elem1,M,indice) :=
			 Block(	[ calc:0,I, exp:0 ],		
			SIMPSUM:TRUE,
			exp:SUBST(I,indice,elem1),			
			exp2:SUM(exp,I,0, M-1 )		
);


Mult2(151 * (100 - I12) + 108 , 100 , I12);
----------------

This evaluates to :
   15100 (100 - I) + 10800

where the I variable of the sum shouldn't be in the result.

I really don't know what to do, (i am new to maxima), i think there 
could be a problem with noun-form against verb-form, but i can't find what.

However, the expression:

sum(subst(i,i2,10*i2),i,0,2);

evaluates correctly to :
       30
So it sounds a bit strange to me.

Could anyone please give me some help ?


--
Mathieu Avila ( mavila@irisa.fr )