Hi philip1
I have never relied on these error codes to solve why the API is throwing and error - just like importing the error codes are often defined by the 1st fatal error - and often not what you need.
An API developer in MYOB will spot this post and MAY be able to give an idea.
If you haven't already - https://developer.myob.com/ is the place to go for a help with these errors - though I never found them helpful.
If this is your 1st attempt at getting connected - take small bites of the apple - not huge bites - try just getting a list of the files you legitimate are allowed access to - this is relatively simple.
Then you just build from there - and the problem is often the coding and encoding - and the language you are using to write this.
And we all use different languages from VB.Net, VC#.NET, MS VBA, PHP, Python etc - and whether you are using the MYOB SDK to connect. I don't preferring to write my own access.
Sorry I cannot be more helpful - I can but figuring out your own API access is really time-consuming.
The Doc