Yes - the Daw is Reaper ver 7.xx and I just installed and tested on another laptop (Toshiba Qosmio x505) Win 64 Home Premium-
The DAW VST3 plugin from BIAB Pro 2024 does indeed work with BIAB Ultra-Pak 2025 - at least for what I tested:
Loaded a MGU from the Demo's folder into the plugin then successfully xfer'd all tracks using ctrl/shift drag master track.
So in my humble opinion WINDOWS 7 LIVES
Anyway I'm not even sure anybody else had the problem - but it seems the call made by the new version of the plugin does not support Win 7 64 bit