Can't open old BUN file

Hey,
 
I'm trying to open an old BUN file from 2006.  Not sure what version of Cakewalk I was using at that time.  I'm trying to open it in Sonar X2.  It acts like it is going to work and is reading a lot of WAV files, but it gets to a point and an error message pops up saying: "Cannot read file".
 
Any advice on how I might be able to get this to load?
 
Thanks!

Make sure you open it in safe mode.  It may have a plugin (or soft synth) that will not open in your current version of Sonar and what is on your computer.

Hold down the shift key while opening the project.  It may open in stages - you can reject opening a plugin when prompted (or all plugins) to see if the file opens with just the midi/audio data basically.  (This is an oversimplification).