Could you try this:
set a trigger variable takes value 1 & 0.
Put the exportToBitmap in the OnOpen trigger
reload your qvw 2 times : 1st time with trigger value = 0 (not trigger onopen's exporttobitmap macro)
2nd time with trigger value = 1 (trigger onopen's exporttobitmap macro).
I hit a problem to use macro to print pdf in on post reload and use the same approach to solve the issue.
Hope will help.
The problem is that ExportBitmapToFile statement works only in opened document mode. I encountered this issue in version 7.5. I thought it would be solved by now, but when upgrading to v9 I found it still persist.
Try "c:\Program Files (x86)\QlikView\qv.exe" /l /nosecurity "QV Document.qvw" in batch as a temporary solution. It will open QV document and reload the data, but it will not save it. Save your document in macro.