In your Pro Tools plugins folder ( usually C:\Program
Files\Common Files\Digidesign\DAE\Plug-Ins ) delete any files with 'BDF'
in the filename

run the 1.5.45Q installer

during the 'Select Components Stage', make sure that RTAS v6 (In
my case) is selected and RTAS v7 is deselected. You must
also install the VST and Stand Alone versions. Deselect the kits
if installed already

That fixed it so all the mix buss faders worked.