Eval function with sum

[raffaello_]

Hi, I'm trying to use this VB funcion:

Function EVAL(rg As Range)
Application.Volatile
EVAL = Evaluate(rg.Text)
End Function

It works well in this case:
B3: =CONCATENA("'[Fatturazione";A3;".xls]Foglio1 '!$S$2")
C3: =EVAL(B3)

It doesn't work well in this other case:
G3: =CONCATENA("SOMMA('[Fatturazione";A3;".xls]Foglio1 '!$J:$J)")
H3: =EVAL(G3)

I obtain #"name?" error. Why in the #1 case the function works well an
in the #2 not?

Thank you very muc