First of all, I do own and have Rapture, Rapture Pro, Dimension Pro, and Dimension Pro 1.5 (x2) products in my product area.
 
However, while the Rapture products load fine in SPLAT latest version, Dimension Pro does not.  I get a "Complete Registration: D-Pro" dialogue box.  It is showing the Serial Number correctly for one of my products but the Registration Code listed in my account for that SN does not work.  I tried the other product RC but it doesn't work either (didn't expect it to but tried).
 
I know there's no need to load DP1.5 alone since I have RapturePro but it bugs me since it's a legit product.  Any thoughts?
 
EDIT: to add that this is installed via CCC with everything showing up to date.  Also, the product showing in SPLAT which won't register is a different version (one of two DP1.5 products listed in my account) than shows in CCC which shows the 2nd of the two products listed in my account.  Huh?

Okay, I tried uninstalling DP from Windows Add/Remove Programs and tried reloading DP from CCC.  That didn't work either - still get registration error.
 
So, correct me if I'm wrong but Rapture Pro contains ALL of the DP sounds anyway so I really don't need DP and can delete the 3 gig of DP content on my Samples drive?  Then I will just Hide DP in CCC as it only gives two options on Right-click: i.e. "Hide this product" or "Delete files"

If you installed the DPro packages under RPro all the programs and samples from DRpo would be in the RPro sample and program libraries and the samples and programs installed by DPro would be rendundant. AFAIK, the only programs that do not play properly in RPro are the VB3 programs which came with DPro Expansion Pack 1. These programs have a lot of special features tied to the DPro UI which RPro does not replicate.
 
FWIW, to register DPro after manually installing it, run the stand alone version as administrator and use the latest activation codes from your account.

Thanks for the reply scook.  I will try installing manually and report back.
 
EDIT: I might add that I actually have 3 DP1.5 products listed in my account but while they have different SNs, the download page for all of them are the same SN which is actually different than the one that shows in CCC (one of the three does match CCC but SN product isn't available for download).  I've PM'd Lance about it.

Nope, installing manually fails to install.  While the download page from my account shows the same product SN & RC, it does not accept any of the RCs listed including the one shown on the download page.

When uninstalling DPro you may need to remove
HKEY_LOCAL_MACHINE\SOFTWARE\Cakewalk Music Software\dp
before reinstalling.
 
 

Okay, I took a look through the registry but didn't change anything.  I'll try that now.

Better still here are the clean install instruction http://www.cakewalk.com/Support/Knowledge-Base/2007013238/Clean-Install-Dimension-Pro-for-Dimension-Pro-1-5-full-installer
 
they still look current to me

I didn't find the dp directory under HKEY_LOCAL_MACHINE\SOFTWARE\Cakewalk Music Software but did find it under HKEY_USERS\HKEY_USERS\S-1-5-21-2544713292-1054752897-3434999625-1001\SOFTWARE\Cakewalk Music Software
 
Okay to remove it from there?

I would reboot before doing anything else and work from the clean install instructions provided above. Do not search the registry for additional entries. The only ones you want to affect in the clean install instructions. If the entries are not there, it is one less thing you have to do.