I have a picturebox that I have assigned a bitmap to its image property.

I have this code that throws exceptions periodically. Typically when it is called there are 2500 points in the queue.
Periodically means I have to push the button that adds points(2500) to the queue as fast as possible for a period of time.

Code:
        Dim pt As Point
        Try
            Do While newPTS.Count > 0
                If newPTS.TryDequeue(pt) Then
                    PBbm.SetPixel(pt.X, pt.Y, PBbmDotColor)
                End If
            Loop
        Catch ex As Exception
            Dim s As String = String.Format("X: {0}  Y:{1}  {2}", pt.X, pt.Y, ex.Message)
            AddToError(s)
        End Try
I know that the points being set are within the bounds of the bitmap.

PBbm is the bitmap
newPTS is a queue of points

The errors
X: 446 Y:170 Object is currently in use elsewhere.
X: 34 Y:549 Object is currently in use elsewhere.