[CoinMp] How to use CoinMP.Dll in Visual Basic (Excel)

[design at np-soft.ru]

I have tried to use CoinMP.Dll from Visual Basic. The follow declaration
of function had created:

Public Declare Function CoinInitSolver Lib "CoinMP.dll" (ByVal LicenseStr
As String) As Long

Then I have tried to call the function:
    Dim s As String
    s = Chr(0)
    CoinInitSolver s
But error "Bad Dll calling conversion" had happened... Why? The CoinMP.Dll
was downloaded coin-or.org site...