Below the article lists several must-haves that appear to do a similar job - should I install and run these or is MWBAM sufficient?
You have AVG Antivirus installed alongside with Malwarebytes Premium and also the Windows embedded Firewall. This is a very good combined protection layer which should be enough to guarantee your computer protection.
I would not install any further security programs. If you do that, besides not being necessary it will probably slow down your system.
The only thing that may be necessary if needed (I mean if you notice any errors or computer slowness/freezes or crashes), is to add exclusions from AVG Antivirus to Malwarebytes Premium and vice-versa, in order they do not conflict to each other due to their real time protection. Please do this ONLY if you are still experiencing any strange behavior like computer slowness or freezes/crashes (even if temporarily) on your system.
Please read the articles in the following links and add exclusions in both programs:
Antivirus Slowing Your PC Down? Maybe You Should Use Exclusions
How to Run Malwarebytes Alongside Another Antivirus
These are the Malwarebytes files to be added to AVG Exclusions List:
Also please exclude the following folders too: (The complete folder)
the programme that I am having real trouble getting to work is called Encore Pro. Part of it is a database and I suspect that is what the error message relates to.
I'm not familiar with that program. However, I suggest you try to run it again after adding the exclusions on both programs (AVG and Malwarebytes).
Please let me know how you get on with this.