I have had mixed success in opening old .bun files created in CWP8.... some opened OK and others were "corrupted" and did not open.
I would suggest opening the file in the old machine then saving it as a normal project into a USB drive. Be sure it saves all the audio data with it in the same folder. ..... then, attempt to open it from the USB drive on the new machine. It should open and run properly,,,,, just save it into a new folder on the new machine.