是用自己写的dll做的...
有两个dll
CursorPos.dll
windowRfromPoint.dll

代码
Dim cur As CursorPos
Dim winForm As windowsRfromPoint
Private Sub Form_Load()
Set cur = New CursorPos
Set winForm = New windowsRfromPoint

End Sub

Private Sub Timer1_Timer()
cur.CurrsorPos '获得鼠标的位置
winForm.X = cur.PosX 'cur.PosX鼠标的X坐标指定给某个窗体winForm.X
winForm.Y = cur.PosY '.......Y..................................
Text1.Text = winForm.windowsRfromPoint '获得指定点窗体的句柄
End Sub

运行程序后只要把鼠标移到你想得到句柄的窗体的标题栏就行了!

你没有注册dll当然有错了
用regsvr32命令注册需要的组件

注册 regsvr32 XXX.dll (这两个CursorPos.dll windowRfromPoint.dll)
在程序的目录下)

卸载 regsvr32 -u XXX.dll

运行-->>cmd
>regsvr32 路径\CursorPos.dll
.................................