GDI Object leak??

I'm using a TransparentBlt sub I found elsewhere on the net. I have a timer that calls the sub a couple times per second, and apparently there is some sort of leak because after a while the program stops drawing and Task Manager reports that it is using 10,000 GDI Objects. Can someone please help me find the leak, as I have no knowledge of GDI objects.
The TransparentBlt Sub

VB Code:

Sub TransparentBlt(dsthDC As Long, srchDC As Long, x As Integer, y As Integer, Width As Integer, Height As Integer, TransColor As Long)
 
 Dim maskDC As Long      'DC for the mask
 Dim tempDC As Long      'DC for temporary data
 Dim hMaskBmp As Long    'Bitmap for mask
 Dim hTempBmp As Long    'Bitmap for temporary data
 
 'First, create some DC's. These are our gateways to associated
 'bitmaps in RAM
 maskDC = CreateCompatibleDC(dsthDC)
 tempDC = CreateCompatibleDC(dsthDC)
 
 'Then, we need the bitmaps. Note that we create a monochrome
 'bitmap here!
 'This is a trick we use for creating a mask fast enough.
 hMaskBmp = CreateBitmap(Width, Height, 1, 1, ByVal 0&)
 hTempBmp = CreateCompatibleBitmap(dsthDC, Width, Height)
 
 'Then we can assign the bitmaps to the DCs
 hMaskBmp = SelectObject(maskDC, hMaskBmp)
 hTempBmp = SelectObject(tempDC, hTempBmp)
 
 'Now we can create a mask. First, we set the background color
 'to the transparent color; then we copy the image into the
 'monochrome bitmap.
 'When we are done, we reset the background color of the
 'original source.
 TransColor = SetBkColor(srchDC, TransColor)
 BitBlt maskDC, 0, 0, Width, Height, srchDC, 0, 0, vbSrcCopy
 TransColor = SetBkColor(srchDC, TransColor)
 'The first we do with the mask is to MergePaint it into the
 'destination.
 'This will punch a WHITE hole in the background exactly were
 'we want the graphics to be painted in.
 BitBlt tempDC, 0, 0, Width, Height, maskDC, 0, 0, vbSrcCopy
 BitBlt dsthDC, x, y, Width, Height, tempDC, 0, 0, vbMergePaint
 
 'Now we delete the transparent part of our source image. To do
 'this, we must invert the mask and MergePaint it into the
 'source image. The transparent area will now appear as WHITE.
 BitBlt maskDC, 0, 0, Width, Height, maskDC, 0, 0, vbNotSrcCopy
 BitBlt tempDC, 0, 0, Width, Height, srchDC, 0, 0, vbSrcCopy
 BitBlt tempDC, 0, 0, Width, Height, maskDC, 0, 0, vbMergePaint
 
 'Both target and source are clean. All we have to do is to AND
 'them together!
 BitBlt dsthDC, x, y, Width, Height, tempDC, 0, 0, vbSrcAnd
 
 'Now all we have to do is to clean up after us and free system
 'resources..
 DeleteObject (hMaskBmp)
 DeleteObject (hTempBmp)
 DeleteDC (maskDC)
 DeleteDC (tempDC)
End Sub

My timer code

VB Code:

Private Sub Timer_Timer()
On Error GoTo errhandle
Dim i As Byte
 Me.Cls
 BitBlt Me.hdc, 0, 0, Me.Width, Me.Height, DesktopDC, 0, 0, vbSrcCopy
 
 If SpriteCount > 0 Then
 For i = 1 To SpriteCount
  If Sprite(i).Shown Then
   With Sprite(i)
   picCurrentSprite.Cls
   If .Reversed Then StretchBlt picCurrentSprite.hdc, .Width - 1, 0, -.Width, .Height, .hDCofRefPic, .xSrc, .ySrc, .Width, .Height, vbSrcCopy
   If Not .Reversed Then BitBlt picCurrentSprite.hdc, 0, 0, .Width, .Height, .hDCofRefPic, .xSrc, .ySrc, vbSrcCopy
   TransparentBlt Me.hdc, picCurrentSprite.hdc, .Left, .Top, .Width, .Height, GetPixel(.hDCofRefPic, 1, 1)
   If .Reversed Then .Left = .Left + .WalkSpeed
   If Not .Reversed Then .Left = .Left - .WalkSpeed
   .ySrc = .ySrc + .Height
   If .ySrc >= .TotalHeight Then .ySrc = 0
   If .Left + .Width < 0 Then .Shown = False
   If .Left > (Screen.Width / Screen.TwipsPerPixelX) Then .Shown = False
   End With
  End If
 Next i
 End If
 
 Exit Sub
errhandle:
 Debug.Print Err.Description
 End
End Sub

Edit: I'm pretty sure the leak spawns from the TransparentBlt sub, because I commented out the call to that sub in my timer code, and there is no longer a leak.

Try setting each object to nothing also...

Apparently, you should not delete a bitmap that is still selected into a DC. Capturing the return value of API functions should assist in debugging your code. Regardless, try this

VB Code:

'Then we can assign the bitmaps to the DCs
 'hMaskBmp = SelectObject(maskDC, hMaskBmp)
 'hTempBmp = SelectObject(tempDC, hTempBmp)
 hMaskOldBmp = SelectObject(maskDC, hMaskBmp)
 hTempOldBmp = SelectObject(tempDC, hTempBmp)
'...
 'Now all we have to do is to clean up after us and free system
 'resources..
 SelectObject(maskDC, hMaskOldBmp )
 SelectObject(tempDC, hTempOldBmp )
 DeleteObject (hMaskBmp)
 DeleteObject (hTempBmp)