So i'm using the latest version of platinum and I can't seem to get ANY of the prochannel compressors or gate to properly sidechain. I've done it before. I can set up the sends and everything. They just don't seem to be getting signal from the sidechain.

OK I opened another blank project to investigate and it seems to be working. It just won't work in the project i'm working on for some reason. :(

possibly your routing ?
I don't side chain often but could it be there is an issue with the signal path ?
if anything, my comment is a bump

OK. I simplified my project to try and show what's happening. It turns out the sidechain connection seems to be working just fine when the track the sidechain input is coming from is soloed. However, when I allow the signal to pass through the track with the compressor the sidechain stops triggering the compressor or having any effect at all.

In my example the kick track has a send to the CA-2A's sidechain in the prochannel of KeyEcho. Hopefully the gif speaks for itself.

https://drive.google.com/open?id=0B1hvshJiHZ8IbWduQ0FLM3lWYVE 

I had a similar issue.  In one project I couldn't get Melda's MDynamicEq to sidechain.  I tried it on another project and it worked perfectly.  Mysterious.