bonjour j' ai un problème

avec mon code et je pense que vous pourrez le régler, avec mon code j' ai le message erreur "indice en dehors de la plage " sur la ligne " Graph(x, 1) = som1 'X"
donc voici mon code pourriez vous m'aider a trouver se qui ne va pas merci

Private Sub Form_Load()
M1 = 30
A0 = 1
DELTAV = 5 - 2
M = 12.5 + (1.5 * DELTAV)
A = 4 - (0.8 * DELTAV)
B = 90.5 - (0.5 * DELTAV)
K1 = 1.1 * (1 - (0.006 * ((M1 * (A0 ^ 0.5)) - 40))) * (1 - (0.04 * DELTAV))
µ = 0.1 + (0.003 * ((M1 * (A0 ^ 0.5)) - 40))
e = 25 - 4
P = 1
Z1 = 0.25 * 25
Z1 = Int(Z1)
vN1 = 2 * P
vN2 = 4 * P
vN3 = 8 * P
vN4 = 16 * P
Fta1 = K1 * (vN1 ^ µ) * (M1 * (A0 ^ 0.5))
Fta2 = K1 * (vN2 ^ µ) * (M1 * (A0 ^ 0.5))
Fta3 = K1 * (vN3 ^ µ) * (M1 * (A0 ^ 0.5))
Fta4 = K1 * (vN4 ^ µ) * (M1 * (A0 ^ 0.5))
P1 = (0.9 * Fta1) / e
P2 = (0.9 * Fta2) / e
P3 = (0.9 * Fta3) / e
P4 = (0.9 * Fta4) / e
LogP1 = Log(P1) / Log(10)
LogP2 = Log(P2) / Log(10)
LogP3 = Log(P3) / Log(10)
LogP4 = Log(P4) / Log(10)
logn1 = Log(vN1) / Log(10)
Logn2 = Log(vN2) / Log(10)
Logn3 = Log(vN3) / Log(10)
Logn4 = Log(vN4) / Log(10)
Dim Graph() As Single
Dim x As Integer
For x = 1 To Val(Z1)
som1 = ((M * (Log((0.9 * Fta1) / Val(Z1)) / Log(10))) + (A * logn1) + B)
som1 = Format(Val(som1), ".0")
Graph(x, 1) = som1 'X
Graph(x, 2) = x 'Y
Next x
For x = Val(Z1) To Val(Formdoncomp.e1.Text)
somm1 = ((M * (Log((0.9 * Fta1) / Val(x)) / Log(10))) + (A * logn1) + B)
somm1 = Format(Val(somm1), ".0")
Graph(x, 1) = somm1 'X
Graph(x, 2) = x 'Y
Next x
MSChart2.chartType = VtChChartType2dXY
MSChart2 = Graph
MSChart2.Plot.UniformAxis = False
End Sub
Nous entrainerons nos coeurs et nos corps afin de pouvoir réaliser l'impossible.