How to plot a summation?

[RodrigoPontes]

No, didn't fix it. I tried modifying the code a bit, as to make it return the summation only when X>0 and X<10. Now it doesn't crash, but in the interval from 0 to 10, nothing is plotted, like the program didn't return anything. Here is the code:

EXPORT sumplot(X)
BEGIN
IF X < 1 THEN
return 0;
END;
IF X > 10 THEN
return 0;
END;
return CAS.sum("N","N",0,X);
END;

Maybe CAS is returning something the plotting does not understand?