While Cakewalk's User Forum is without question the best that exists on the Internet, Cakewalk's On-line support is just about the worst that exists.  I've tried several times to certify or re-activate the LAME software that I bought and paid for  a few years ago to export MP3 audio.  It is very nearly impossible to do.  Any suggestions?  
 
I've also been trying to get up to speed using Dimension Pro 1.5 installed with my Platinum DAW.   I am trying to bring up a Subtractive Synth so that I can work through Coursera's "Creating Synthesizer Sounds for Electronic Music (Project-Centered Course)" through Berklee College of Music.   Nowhere do I find a primer to even begin to show me how to use it?  I welcome your input!

If you want to learn subtractive synth programming, I would suggest that you use z3ta because it emulates the classic subtractive synth.  DPro is basically a sample playback synth (rompler).

Hi. Others may know better about all of this.
I use Aarons MP3 patch found here for MP3 conversion.
There are some videos of Dimension Pro on YouTube. Here is one.
https://www.youtube.com/watch?v=-2bRI-GP79k
All the best.
 

Have you tried sending an email about the MP3 encoder? A Cakewalk staffer said last week that their "Customer Service team has been very successful at responding to inquiries rapidly, almost always within the same business day a request has come in." YMMV
 
BTW, LAME is free and you can set that up without any activation.
 
As far as Dim Pro, I would reference the help files which should be included, but here they are, just in case:
http://www.cakewalk.com/Support/Knowledge-Base/2007013200/Dimension-Pro-1-5-Help-files

Check out video tutorials.
Dimension Pro In Depth
Virtual-Instruments-Revealed
 
They might be at the Cakewalk store.
 
As for subtractive synthesis try a free one call Synth 1. 
 

Great book  - https://www.amazon.com/Ca...+Presets+to+Power+User

Brando
Great book  - https://www.amazon.com/Ca...+Presets+to+Power+User

.+1.  A great book by Simon Cann.