Retail POS Development - triggers - get Error Number 13000

Hello,

I am creating an override trigger using the retail SDK as the basis of the code using the AX 2012 R3 VM.

i wanted to try something very simple at first:  "Hello World" message box - so there isn't a lot of code in the class.  And I have signed the assembly as well. 

When I deploy and run the POS, I get: "error number: 13000 Could not load all external service modules".

I'm not sure how to fix this or decipher it as the code was based on the SDK class.

I've done the tutorial Application Trigger a while ago on an older AX 2012 R2 VM and it worked without a hitch. 

So I'm a little bit lost on how to resolve.
Any suggestions or advice is greatly appreciated.

thanks for your time and help