OpenBridge Modeler: Define Beam Layout with Aux Alignments

I'm trying to model a bridge in OpenBridge Modeler where the beams are not parallel to the deck fascia or alignment (curved deck with straight beams). It seems to me the only way to model this is to define the beam layout using an Aux Alignment for each beam (or use Aux Alignment for one beam and set the others parallel to this one). I imported the Aux Alignment and assigned it to a fascia beam with the spacing as 0 since I want the beam line as the Aux Alignment. However, when I try this and click to validate or save the beam layout, I get an error with a red X: 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. Everything seems right to me: it accepted the alignment and there is no red text indicating anything is wrong.

Is there a better way to model a bridge with this type of geometry?

What does this error mean?

Are there any tutorials explaining how to use the Aux Alignment feature?