cubase vst 5.1 (mac) update to 5.1r1 troubles

I’ve been running vst 5.1 for years with no issues at all on a imac g4 flat panel running os9.2.

I saw an update to 5.1r1 so thought it might give me new features. After installing this update I cannot get cubase to accept my quattro audiosport as my audio source. The quattro shows up in my midi configuration as it should, and I can get the quattro control window to open directly, outside of cubase. But in the audio set up window of cubase you can see the quattro in the drop down menu but it won’t open it, it reverts back to apple sound manager.

any assistance or ideas would be awesome - I’m pulling my hair out - never had problems until this update.

already tried reinstalling 5.0 from original cdrom then reinstalling the update but no good; also tried reinstalling the quattro driver - and putting it in the asio folder…

thanks in advance!!!