mxo not recognized after updates

Note my software versions and hardware in my signature.

It was working fine, but after a bout with bad ram, clean install and updates, including download and re-install of mxo new drivers, fcp cannot access mxo.

FCP shows the mxo settings in the video playback list, but it does not show the mxo audio in the audio list. I cannot play back either one.....

When I hit command f12 for play all frames, i get the message "the specified hardward could not be found, check your camera connection".

Yes, I've been through every single av and other setting a gazillion times and can't find the problem there.

mxo tech support has not been able to find the problem.

I have a unique setup because my acd serves as both primary and secondary display. I don't even remember how or why it worked before, but now it does not.

I've trashed prefs, repaired permissions.

I'm wondering if it has something to do with my version of QT or some other update?

I have to stay with Tiger because I do not have the cash flow to buy Leopard and a new version of Photoshop.

Here's a summary of the situation:

I used to have the mxo working to preview HD video as I edited my ProRes422 8 bit projects. I had to "make do" using my 23" ACD (for resolution) and simultaneously watch my old NTSC 4:3 monitor for color/black levels.

This used to work despite the fact that I was only able to use one dvi port on my X800XT video card. (Please take my word for it, there is no adapter currently made for the secondary port to go to apple's propietary dvi to vga- let's not revisit that in this discussion).

Any chance this might be a simple thing like updating to QT6, assuming that update won't break something else?

PowerPC G5 DP2.3, 4GB DDR SDRAM, ATI X800XT, OSX.4.11, QT 7.5.5, FCStudio2, FCP 6.0.5 Sonnet 5 Bay SATA (RAID or JBOD as needed), ACD 23" & Sony NTSC Monitor via Matrox v.1
Sony ZIU hdv, edit w.ProRes