You might want to try a fresh install of RTW before installing BI. I assumed/hoped the install would overwrite the changes I made to the game so I backed up my modified files and installed BI. Whilst the separate BI executable file and campaign runs perfectly, RTW itself no longer works. Seems a few things have changed but the install failed to replace some of my modified files, so it looks like a complete re-install of RTW and BI is in order. That will be such fun!