Compile issue using Solver

Sub Macro2()
'
' Macro2 Macro
'

'
    Range("G5").Select
    SolverOk SetCell:="$G$5", MaxMinVal:=2, ValueOf:=0, ByChange:="$G$4", Engine:=1 _
        , EngineDesc:="GRG Nonlinear"
    SolverOk SetCell:="$G$5", MaxMinVal:=2, ValueOf:=0, ByChange:="$G$4", Engine:=1 _
        , EngineDesc:="GRG Nonlinear"
    SolverSolve
End Sub

I got a message box:

"Compile error: Sub or function not defined"

I guess the message refers to function or sub SolverOk.

Anyone can help me. Thanks in advance

>Solution :

You need to create a reference to the Solver object, via the VBA menu Tools > References.