That would be something like:
vb.net Code:
Public Class MyFancyToolStripRenderer
Inherits ToolStripProfessionalRenderer
Protected Overrides Sub OnRenderToolStripBorder( <args will come automatically> )
'Emtpy sub
End Sub
End Class
Note that as soon as you finish writing "Protected Overrides Sub OnRenderToolStripBorder(" it will probably auto-complete and it will add a "MyBase.RenderToolStripBorder" or something like that. The C# code comment tells you to remove that so the base 'render toolstrip border' code does not get called.
I don't know if this will fix your code but it's worth a shot...
If you still don't understand perhaps have a look at my signature for the VS2008 style MenuStripRenderer, you can find a full example on how to use a ToolStripRenderer there.