You want to total text???? or do you mean you want to combine the text into a string??
for "concatenating" text see here
http://www.techonthenet.com/access/functions/string/concat.php
for summing/totally numeric data
Expr: IIf(Isnull([CF1]),0,[CF1])+IIf(Isnull([CF2]),0,[CF2]) etc etc