Running Solver with VBA

I'm using this code to run Solver with VBA. When I run it, there is no solution (or Solver Results dialog box). When I check the Solver Parameters under "Tools" ,I see that the constraints and MaxMinVal are entered correctly. But there are no entries for "Set Target Cell or "By Changing Cells". What have I done wrong?

VB Code:

Sub RunSolver()
 
'Prompt for month number
currMonth = Application.InputBox(Prompt:="Enter month number:", Type:=2)
 
'Clear previous Solver settings
SolverReset
         
    ' Solver Options...
    Call SolverOptions(MaxTime:=100, Iterations:=200, Precision:=0.0001, AssumeLinear _
        :=True, StepThru:=False, Estimates:=1, Derivatives:=1, SearchOption:=1, _
        IntTolerance:=5, Scaling:=False, Convergence:=0.0001, AssumeNonNeg:=True)
  
 
' The Solver will run one month at a time. Using the first month as
' the starting point, use intOffset to determine which month (column)
' to solve for
 
    intOffset = currMonth - 1
 
    ' Set the target cell to a minimum value by changing cells C11:C22 or
    ' an offset of this range
    SolverOk SetCell:=Range("Total_Cost"), MaxMinVal:=2, _
        ByChange:=Range("Ship").Offset(0, intOffset)
    
    ' Add the constraint that Final Inventory <= Capacity
    SolverAdd CellRef:=Range("Final_Inventory").Offset(0, intOffset), Relation:=1, _
        FormulaText:=Range("Capacity").Offset(0, intOffset)
    
    ' Add the constraint that Final Inventory >= Safety Stock
    SolverAdd CellRef:=Range("Final_Inventory").Offset(0, intOffset), Relation:=3, _
        FormulaText:=Range("Safety_Stock").Offset(0, intOffset)
 
    ' Add the constraint that shipments to customer = customer demand.
    SolverAdd CellRef:=Range("Net_Flow_Cust").Offset(0, intOffset), Relation:=2, _
        FormulaText:=Range("Demand_Cust").Offset(0, intOffset)
    
    ' Add the constraint that shipments from PM = PM Production.
    SolverAdd CellRef:=Range("Net_Flow_PM").Offset(0, intOffset), Relation:=2, _
        FormulaText:=Range("Supply_PM").Offset(0, intOffset)
 
    ' Add the constraint that shipments from WHSE >= WHSE Demand.
    SolverAdd CellRef:=Range("Net_Flow_WHSE").Offset(0, intOffset), Relation:=3, _
        FormulaText:=Range("Demand_WHSE").Offset(0, intOffset)
    
    ' Solve the model and keep the final results.
    SolverSolve UserFinish:=False
    'SolverFinish KeepFinal:=1
 
End Sub

With the solver addin it will need to be loaded, which I am presuming it is and if you are calling this from a different workbook then you will need to use Application.Run

e.g.

VB Code:

Application.Run "solver.xla!SolverReset"

Thanks. After much hunting around, I found the problem is related to an issue with the version of SP-3 I'm running with Excel 2000. I've contacted MS for a patch. In the meantime I'm using an older version of solver.xla.