The LoopBe1 driver should not be selected for both In and Out. This will cause MIDI feedback. I believe it has a fail-safe that mutes the driver if it detects MIDI feedback, so that could be what is going on.
If you are using the driver for output, then you need another program to use it as input. For example, PowerTracks or RealBand could receive MIDI signals and play out through a DXi synth.
If the Vocalist is hardware, then the LoopBe1 driver would not be necessary. In that case their should be some kind of output driver available in the Band-in-a-Box MIDI output driver list.