It could be a routing issue, except for the synth the routing is the same for TTS-1, Dimension LE and DimPro. Does the stand alone DimPro play correctly?

 
Notice the top input its where you right click to open the program browser for Dim Pro. Clicking on a program will load it.  

Make sure that the "input" of the audio track (in your stated case, track two) is set to DimPro, channel 1 and the "output" is set to either the main bus or your main audio outs.
 
You might also try loading an instance of DimPro and choosing "Instrument Track" instead of breaking the instance into two tracks (midi and audio).  With everything in one track, X3 should set everything to your default midi/audio gear...

Well, guys, believe it or not, it appears it might have been a product registration problem.  When I tried to play the stand alone version, I got prompted to enter my registration code.  After having some problems doing that, I un-installed and re-installed it and completed the registration process.  It works as advertised now.
 
(In my defense, I tried to complete the registration by including the codes from my account at Cakewalk.  I got it to work this time by using the codes from a previous purchase.)
 
Sorry for the diversion but maybe it's a lesson learned for all of us.
 
Thanks to all for trying to help.

Glad you got it resolved. Please edit the subject in the original post and add [Solved] to the subject. This helps everyone know the issue is resolved and aids when searching for solutions.

>>Well, guys, believe it or not, it appears it might have been a product registration problem.  When I tried to play the stand alone version, I got prompted to enter my registration code. 
 
I believe I had the same (similar?) issue with Dimension Pro and Rapture when I installed long ago.  I think they have/had to be started as stand alone then registered as an Admin for it to work. 
 
http://www.cakewalk.com/S...using-the-correct-code

Alls well that ends well!