[Update] Scratch Live 2.4.4 has since been released and has fixed these issues with the faders on Rane mixers. It is recommended that you upgrade to this version.
There is an issue with final release of Scratch Live 2.4.3 which has broken the ability for MixEmergency to use the faders on Rane mixers.
Serato has been made aware of this issue, and will work towards fixing this in the next release of Scratch Live.
In the meantime, I recommend that users:
a) Revert to using Scratch Live 2.4.2
b) After launching Scratch Live 2.4.3, enable and then disable Serato Video in the Setup screen of Scratch Live
While I can't recommend using the public beta versions of Scratch Live, it has been noted that a number of users are using Scratch Live 2.4.3 public beta 3 successfully.