The following message appears during the Printer Driver converting process, after trying to open a old style *.plt Printer Driver :
Unhandled exception has occurred in a component in your application. If you click Continue, the application will ignore this error and attempt to continue.
Object reference not set to an instance of an object.
The SIZE record in the *.plt printer driver needs a minimum setting: /units=mm
Add /units=mm to the SIZE record (save the *.plt file) and start converting the *.plt file once again
Example:
size=(297,210) /units=mm /num=26/off=(-5.5,-5.5) /name=a4 ; DIN A4
http://communities.bentley.com/products/microstation/microstation_printing/w/wiki/using-microstation-plot-driver-to-create-and-convert-printer-driver-configuration-files.aspx