I've tried it in a couple of different devices and it's in and out for me.
 
It is the demo version, but I just installed it.
 
I downloaded the demo from here...
http://www.store.cakewalk.com/b2cus/ProductInfo.aspx?productid=30-AGSZ2.00-30E
 
Basically, every couple of seconds the audio goes silent for a few milliseconds.
 

I am not sure I understand what you meant by installing it in a couple of 'devices'.
 
From the documentation on the company's web site, it looks like it is meant to be used with its own included synth.
 
Here is from their site:
 
"Do I need an actual synth to use this program?
 
No, Syntorial comes with a custom, quality, built-in soft synth, used throughout the entire program.
 
Can I use my own synth?No.
 
In order to provide you with feedback on your patch programming, Syntorial needs to interact with the synth in a very specific and special way, that only Syntorial's synth is equipped to handle."
 
Bob Bone
 

Hey - gswitz, 
 
Here is a link to another thread, to a post from what looks like the creator of Syntorial:
 
http://forum.cakewalk.com/FindPost/3046240
 
Perhaps you could shoot him a private message or otherwise get him involved in this thread.
 
Bob Bone
 

A person named Joe at the company is helping me. I did buy the product. It's pretty cool.
 
I haven't worked out the intermittent muting, but the Synth that comes with it does work in Sonar and I am forging ahead through the lessons.
 
So far, I've completed 17 of 199 lessons. Oh my!

When I say I tried it in multiple devices I mean that after installing it on my computer,
I played the audio through my RME UCX.
When I couldn't resolve the mutings on the UCX, I tried running as Administrator.
I tried turning up the buffers on the UCX.
I tried Turning off the UCX and listening through my monitor (which has its own speakers).

Wow!  I am glad you are so studious over a World Cup weekend.  (perhaps you are from Spain and have lots of free time, now that they are eliminated).
 
Glad someone is helping you through it all, and glad you found something to help you learn to create new sounds.
 
Bob Bone