ByRef argument type mismatch

Sub IFD()
'Input parameters from worksheet
Dim iMax As Integer: iMax = Range("B3").Value
Dim jMax As Integer: jMax = Range("B2").Value
Dim maturity As Double: maturity = Range("B4").Value
Dim strike As Double: strike = Range("B5").Value
Dim riskFree As Double: riskFree = Range("B6").Value
Dim sigma As Double: sigma = Range("B7").Value
Dim dprice As Double: dprice = Range("B8").Value
Dim qcontract As Double: qcontract = Range("B10").Value
Dim knock As Double: knock = Range("B11").Value
Dim settle As Double: settle = Range("B12").Value
'Perform the matrix calculation
Dim Fvec() As Double: ReDim Fvec(0 To jMax)
Call CalAccumulatorPrices(knock, settle, qcontract, maturity, strike, riskFree, sigma, iMax,  _
jMax, dprice, Fvec())
'Put results back to worksheet
Dim i As Integer
For i = 0 To jMax: Range("C15").Offset(i, 0) = Fvec(i): Next i
End Sub

Sub CalAccumulatorPrices(knock As Double, settle As Double, qcontract As Double, maturity As  _
Double, strike As Double, riskFree As Double, sigma As Double, _
iMax As Integer, jMax As Integer, dprice As Double, ByRef Fvec() As Double)
Dim dtime As Double: dtime = maturity / iMax
Dim Lr As Integer
Dim i As Integer
Dim CIRsigma As Double: CIRsigma = sigma * (Lr * dprice) ^ 1 / 2
'Construct the matrix P and Q
Dim Pmatrix() As Double: ReDim Pmatrix(0 To jMax, 0 To jMax)
Dim Qmatrix() As Double: ReDim Qmatrix(0 To jMax, 0 To jMax)
Pmatrix(0, 0) = Exp(riskFree * dtime)
Pmatrix(jMax, jMax) = 1
Qmatrix(0, 0) = 0
Qmatrix(jMax, jMax) = 1
For Lr = 1 To jMax - 1
Pmatrix(Lr, Lr - 1) = 0.25 * ((Lr * riskFree * dtime) - (Lr ^ 2 * CIRsigma ^ 2 * dtime))
Pmatrix(Lr, Lr) = 1 + 0.5 * (riskFree * dtime) + (Lr ^ 2 * CIRsigma ^ 2 * dtime)
Pmatrix(Lr, Lr + 1) = -0.25 * ((Lr * riskFree * dtime) + (Lr ^ 2 * CIRsigma ^ 2 * dtime))
Next Lr
For Lr = 1 To jMax - 1
Qmatrix(Lr, Lr - 1) = -0.25 * ((Lr * riskFree * dtime) - (Lr ^ 2 * CIRsigma ^ 2 * dtime))
Qmatrix(Lr, Lr) = 1 - 0.5 * (riskFree * dtime) + (Lr ^ 2 * CIRsigma ^ 2 * dtime)
Qmatrix(Lr, Lr + 1) = 0.25 * ((Lr * riskFree * dtime) + (Lr ^ 2 * CIRsigma ^ 2 * dtime))
Next Lr
'Initialize the option vector according to the payoff condition
For Lr = 0 To jMax: Fvec(Lr) = Payoff(Lr * dprice, strike) * qcontract: Next Lr
'Perform the iteration
For i = 1 To iMax
Call SolveAxb(Pmatrix, Qmatrix, Fvec, Fvec, jMax + 1, 0, 0, 0)
Call Boundary(Fvec, jMax, dprice, knock, settle)
Next i
End Sub

Function Payoff(strike As Double, price As Double) As Double
Payoff = (price - strike)
End Function

Sub Boundary(ByRef Fvec() As Double, i As Integer, knock As Double, jMax As Integer, settle As  _
Double, dprice As Double)
Dim Lr As Integer
Dim ReferenceV As Double: ReferenceV = iMax / settle
If (i Mod ReferenceV) = 0 Then
Lr = 0
Do While Lr = knock Then
Fvec(Lr) = 0
End If
Lr = Lr + 1
Loop
End If
End Sub