Background Thread causing System.Reflection.TargetInvocationException

[PlausiblyDamp]

I am dealing only with progress bars and datagridviews.
I only access the progress bar in the background thread so that should be clean
I make make all changes to the dgv in the background thread. i pass in the fields and add rows in the background. I also am changing some colors of cells in the background. I the foreground I do get the number of rows in the background and do read information out of the dgv.

That is pretty much your problem then, you are accessing user interface elements from a background thread. This is a big no-no, you can only access the UI from the main UI thread.

http://www.vbforums.com/showthread.p...ding-in-VB-Net is probably something you will find worth a read.