GoTo Blocks of code and when they activate.

General good programming habits is to avoid using goto. It creates sphaghetti code, and can generally be avoided.

For example, in your code above, why not just have the [Error Handling] code within the Else...End If Block? If the same code is used multiple times, then it is a bit more understandable, but a separate function may be more 'clean'.

Note also that Err is an internal variabe, which you can use to determine the type of system error. I would use something like MyErr in your code above, just to avoid potential conflicts.

On to your specific questions:
If false, then, yes, it will run the error handling code and then exit as you have written it.
If true, then your error handling routine will also run since it is right after your [Do more code] block and you do not have anything before it to stop entry (such as Exit Sub).

You can't have something like Exit MyErr.

What would you be exiting exactly anyway?

Err in your code is just a label, it doesn't define a block of code.

As for using Goto if you need this code to run multiple times, how about looping instead?

I wasn't suggesting you duplicate the code.

Still don't see why referencing the code multiple times would require using GoTo.

PS Why can't you use a function? Data is data, doesn't matter whether it comes from a worksheet or a database.

Sounds like you want to
a) use the error handling code from multiple places
b) be able to 'return' from the error handler back to where it was called

That is a subroutine. I understand it may get messy with a variety of file pointers and objects, so I would suggest you either pass them as parameters or use global variables.

Any chance of seeing the code and/or an explanation of what it's meant for?

You could use global variables and not all subs are private.

Access VBA is basically (exactly?) the same as Excel VBA.

Where are you using this code?

What does the code update?

Is it executing a query that updates a table?