Cubasis audio problem

[Rumbler]

I'd be grateful if anyone can help this newbie.
I have Cubasis VST 5.0, which is doing a fine job as a songwriting scratch pad except for one thing: the audio seems to "auto disable" itself whenever I make changes to tempo or edit any of the midi instruments in the piano roll screen. Each time I do this I have to go in to the "options/audio setup/enable/disable audio" and turn it back on. It is soooo frustrating.
Has anyone else found a solution to this?
Any help would be greatly appreciated.

Cheers!