I don't have a 32 bit file path in the 64 bit plugin manager but I still get this:
 
Sonar X1 64 bit
DirectX Instruments (DXi)
Cakewalk TTS-1
Cyclone
Dimension LE (no file path is shown[?])
Groove Player
PSYN II
rgc:audio Pentagon I
Roland GrooveSynth
 
But then, some versions of Sonar list Dimension LE under DirectX Audio Effects. I believe this happens when installing every version of Sonar I have (32 & 64 bit) on the same Windows 10 computer causing the registry to go wacky.
 
I have :
Dimension LE 1.2.0.69 (32 bit)
Dimension LE 1.2.0.7 (32 bit)
Dimension LE 1.3 (32 bit)
Dimension LE & Pro 1.5 (32 & 64 bit)

soens
I don't have a 32 bit file path in the 64 bit plugin manager

If this is the VST scan path setting, it does not matter. DX plug-ins are not scanned. They are registered during installation. AFAIK, 64bit SONAR does not read the 32bit DX registry entries.

Just reading this it seems the OP has been sidtracked into looking for old outdate version when what should be happening is troubleshooting the install of the latest 64 bit version from CCC.
I think the process the OP has gone through has contaminated the install and at no point have I read that the OP 
followed the normal install procedure so I'm not surprised it's not working. 
 
I would ( thinking) uninstalling/ deleting all traces of Dim Pro and follow the proper steps which I believe is simple. 
Open CCC and choose Dim Pro and install. 
I'm certain a dialog opens once it downloads. 
If the if a run prompt pops up then choose run as administrator. 
You should have a desktop icon or something is not right. 
 

Had this problem. Before you reinstall there is a registry hack so the new install won't have the old registry info. WARNING!!!!! If you aren't used to digging around in the registry, get a friend or tech guy to do it for you. What it boils down to is finding all traces of Dimension in the registry and deleting them.
If you don't do this, the new install will start looking for the registry to initialize and if the info doesn't match it will not open.

Thanks, scook for responding.  Yes, this is on 64bit Windows and the intent is to get 64bit DPro for 64bit SONAR.  I checked both "C:\Program Files\Cakewalk\Dimension Pro" and "C:\Program Files\Cakewalk\Shared Dxi\Dimension Pro." but didn't find anything.  This is getting very frustrating.  I contacted Cake Tech support and they e-mailed me with some suggestions but nothing resolved the problem.  I wish they would just call me and do a remote. I've been a Cakewalk customer since 3.1 and customer service has declined greatly.

Thank you to everyone who has responded so far!

scook

soens
I don't have a 32 bit file path in the 64 bit plugin manager

If this is the VST scan path setting, it does not matter. DX plug-ins are not scanned. They are registered during installation. AFAIK, 64bit SONAR does not read the 32bit DX registry entries.

I'm not sure what you mean by "does not read the 32 bit DX entries". They do show up in the plugin manager list which leads one to believe they are being read by Sonar. In fact you can select them in the Insert Soft synth menu. If you do tho, some like Dim LE will not load into a project. You'll get a "Failed to load" message.
 
BTW I installed Dim Pro 1.5 and it works as expected in both dll and exe versions. It's the older ones I now have issues with on occasion.

Tropical Cowboy
Thanks, scook for responding.  Yes, this is on 64bit Windows and the intent is to get 64bit DPro for 64bit SONAR.  I checked both "C:\Program Files\Cakewalk\Dimension Pro" and "C:\Program Files\Cakewalk\Shared Dxi\Dimension Pro." but didn't find anything.  This is getting very frustrating.  I contacted Cake Tech support and they e-mailed me with some suggestions but nothing resolved the problem.  I wish they would just call me and do a remote. I've been a Cakewalk customer since 3.1 and customer service has declined greatly.

 
At one point I had to delete every mention of Dimension in the registry, reboot and reinstall it from scratch. I think running the setup file as administrator helped too.

You should look for 64-bit VST version as I recall. Don't think there is a 64bit DX version.
I did this leap 2010, so memory is not all clear where I found it.
 
I bought standalone DP in 2006 or something, so not one with Sonar.
 
And looking for DX stuff - this is all registry based and can be anywhere on disc.