Compatibility issue in Access 2007

I am working on a MS access database which is cr开发者_如何学JAVAeated in Access 2000, now I converted it into Access 2007. Every thing is working fine except the (bitmap) image change functionality. Based on same condition I need to change the image of command button

If Me.Command127.Picture = Me.cmdLockImage.Picture Then
      Me.Command127.Picture = Me.cmdUnlockImage.Picture
   Else
     Me.Command127.Picture = Me.cmdLockImage.Picture
   End If

Run-Time error 2220, Can't open the file (bitmap).

Please suggest.

Declare public variable in standard module

Dim blnCmd127 As Boolean

Now on page code

If blnCmd127 = False Then
 Me.Command127.PictureData = Me.cmdUnlockImage.PictureData
 blnCmd127 = True
Else
 Me.Command127.PictureData = Me.cmdLockImage.PictureData
 blnCmd127 = False
End If