Hi, and welcome to the forum.

Do you mean the drums for other songs work correctly? If not, the answer may be different depending on whether you mean MIDI drums, or RealDrums. Assuming it's RealDrums, my guess is that you installed the RealDrums to a different location when you reinstalled the program.

Go to Opt., Preferences, RealDrums. Look near the bottom right corner for Use a Custom Location. Is that checked? If so, the location of your Drums fodder for BIAB should be shown there.

We will need to know what you chose when you installed, to be able to help. For example, are you running the program from your internal hard drive but the RealDrums and RealTracks from the PG Music external drive?

If drums for other songs work correctly in BIAB, then it might be that the one problematic song has somehow become corrupted, and you should create a new file and re-enter the song.

Another thing to try whenever BIAB is not behaving correctly, is to do Opt., Return to Factory Settings. Then reboot your computer and restart BIAB.

Also, don't forget that you can always just call PG Music Support, and they can fix you up.