I logged a customer support request over a month ago and not one response (which I'm guessing by my initial forum review is common) so I thought I'd give this a go here.
 
Every time I load a project in Sonar Platinum (only on the first instance of loading a program upon opening Sonar), I get a pop up window that shows as below.  I click OK, and it pops up again and does the same for 5 more various Prochannel Modules (Gloss EQ, Tube Saturation, Console Emulator, another compressor etc).  Then everything works fine, but I must do this, every single time I load any project.  Click ok 6 times then get to work.  Because prochannel modules aren't really something I can 'point to a location' in settings it's not like I can go change a path.  Any ideas?  It'd be greatly appreciated!  Thanks!
 
- Shaun
 

This looks like a custom installation. Make sure all instances of SONAR are installed on the same drive. Then run a vst reset.

Hmm. I only have one instance of Sonar. But because I have two hard drives (one SSD for program files and an HDD for big data) I do have paths pointed to each for various settings in Sonar. Perhaps that has something to do with it?

Looking at the error closer the location reported for the ProChannel module is unusual even for a custom installation. You might want to try a more conventional installation.

I was getting the same messages, except that in my case they referred to ordinary plugins, not ProChannel modules. This started after I set up a custom Plugin Layout and they appeared whenever I opened a project in 32-bit Sonar (X3 or Platinum). I presume that they referred to 64-bit plugins that were not available in 32-bit Sonar. Reverting the the default Plugin Layout made them stop appearing.

Thanks Kev.  Unfortunately I haven't messed with Plugin Layouts at all.  I'm wondering though if there's remnants of older versions of Sonar hanging out on my computer though.  I'll do a registry search for them.

My guess would be that the "hard-coded" (but in the registry) link to the folder where PC modules are installed has got lost.