Are you using ASIO or MME drivers (audio settings window)?

When you play on the Thru track, are you sure that you are in fact hearing the Hi-Q sounds? i.e. the sounds played by the SampleTank DXi synth.

Thru playback can be routed differently depending on whether the song is playing/stopped, and whether using MME/ASIO drivers. There are also two settings that affect this: "ASIO always on" (audio drivers dialog) and 'Route MIDI Thru to MIDI driver" (MIDI Driver Setup dialog)

In any case, to verify if you are hearing SampleTank and not some other MIDI device, you can:
1. Click the Plugins button --> DXi Synth Settings.
2. Choose the Thru track. Provided you have a Hi-Q instrument selected on the Thru track, you should see the SampleTank synth appear.
3. Play some notes by clicking on the Thru piano in Band-in-a-Box, or by playing your keyboard. If you see no activity in SampleTank, then you are not hearing Hi-Q instruments...

Andrew
PG Music Inc.